Chin. Phys. B

Theory and applications of attosecond transient absorption spectroscopy: From atoms to solids

Ennan Cui and Difa Ye(叶地发)

Chin. Phys. B, 2025, 34 (7): 073201. DOI: 10.1088/1674-1056/add1ba

Abstract ( 282 )

HTML ( 0 )

PDF (3660KB) ( 202 )

This review comprehensively explores the theory and applications of attosecond transient absorption spectroscopy (ATAS) in studying ultrafast electronic dynamics across various systems, from atoms to solids. Driven by significant advancements in ultrafast laser technology, such as generating isolated attosecond pulses, ATAS enables detailed investigations of ultrafast electronic processes with unprecedented time resolution. The article introduces the fundamental principles and historical development of ATAS. Applications of ATAS are discussed in three main domains: in atoms, where it has been used to study build-up dynamics of Autler-Townes splitting, Fano resonance, light-induced states, etc.; in molecules, where it has revealed coherent molecular wavepacket dynamics and non-adiabatic dynamics near conical intersections; and in solids, where it has been extended to investigate ultrafast charge carrier dynamics in metals, semiconductors, and insulators. The review highlights the potential of ATAS in developing ultrafast optical switches and petahertz electronics. The ability of ATAS to probe and manipulate electronic dynamics at the attosecond timescale provides a powerful tool for exploring the fundamental limits of electronic and optical processes in materials.

Characterization of cold atoms based on photoionization momentum spectra

Zhixian Wu(吴志贤), Shushu Ruan(阮舒舒), Zhenjie Shen(沈镇捷), Jie Liu(刘杰), Xinglong Yu(余兴龙), Lifeng Chen(陈利丰), Bing Zhu(朱兵), Xincheng Wang(王新成), and Yuhai Jiang(江玉海)

Chin. Phys. B, 2025, 34 (7): 073202. DOI: 10.1088/1674-1056/add00d

Abstract ( 237 )

HTML ( 0 )

PDF (755KB) ( 86 )

We propose a method to characterize the features of a cold strontium cloud in a magneto-optical trap (MOT) through the photoionization of cold Sr atoms in a custom-designed reaction microscope. Sr atoms in the dark state of $\mathrm{5s5p \, ^3P_2}$ populated via the cascade transition $\mathrm{5s5p \, ^1P_1 \rightarrow 5s4d \, ^1D_2 \rightarrow 5s5p \, ^3P_2}$ accumulate a significant fraction, giving a long lifetime of 520 s. These atoms in the dark state are subsequently trapped by the gradient magnetic field of the MOT. By scanning the Sr$^+$ momentum distributions ionized with an 800 nm infrared femtosecond laser, we are able to outline the size of $\sim0.55$ mm in radius and the temperature of $\sim0.40$ mK for the dark-state atoms, which is significantly cooler than the MOT temperature of 3.3 mK trapped in the 461 nm. The size of MOT exhibits an oblate spheroidal distribution with a radius of approximately 0.35 mm and 0.55 mm, extracted with momenta of photoion and absorption imaging, respectively. The results using the photoion momenta are consistent with the expected results from absorption imaging, which confirms the method's reliability. The advantage of this method is the ability to simultaneously characterize the distribution information of atoms in different initial states within the cold atomic cloud.

Isotopic effects in two-body fragmentation process of water dications induced by electron-impact ionization

Xiaorui Xue(薛晓睿), Jiaqi Zhou(周家琪), Xintai Hao(郝鑫泰), Lei Wang(王磊), Peng Li(李鹏), Qibo Ma(马启博), and Xueguang Ren(任雪光)

Chin. Phys. B, 2025, 34 (7): 073401. DOI: 10.1088/1674-1056/add4fd

Abstract ( 210 )

HTML ( 0 )

PDF (792KB) ( 85 )

The two-body fragmentation dynamics of water isotopologues dications ($\rm{{H_2O}^{2+}}$, $\rm{{HOD}^{2+}}$, and $\rm{{D_2O}^{2+}}$) induced by 200 eV electron impact is investigated. Two fragment ions and an emitted electron are detected in coincidence, and their momentum vectors are determined by employing a reaction microscope. The complete kinematical information of four two-body fragmentation channels of $\rm {H}^{+} + \rm {OH}^{+}$, $\rm {H}^{+} + \rm {OD}^{+}$, $\rm {D}^{+} + \rm {OH}^{+}$, and $\rm {D}^{+} + \rm {OD}^{+}$ is obtained. By analyzing the projectile energy-loss spectrum, the initial electronic state of the two-body dissociation channel is determined. Upon examining the kinetic energy release (KER) distributions of the four fragmentation channels, a clear difference is found between the two-body fragmentation channel $\rm {H}^{+} + \rm {OD}^{+}$ and the other three channels. The isotopic effect in the two-body fragmentation is demonstrated by the analysis of the relative yields of the two-body fragmentation channels originating from different isotopologues, which shows preferential cleavage of the O-H bond over the O-D bond. These results provide deeper insight into the microscopic dynamic mechanisms in water radiolysis.

Observation of a long-range unidirectional charge density wave in kagome superconductor KV₃Sb₅

Xingwei Shi(石兴伟), Xiao Liu(刘潇), Geng Li(李更), Zhen Zhao(赵振), Haitao Yang(杨海涛), Xiao Lin(林晓), and Hong-Jun Gao(高鸿钧)

Chin. Phys. B, 2025, 34 (7): 077101. DOI: 10.1088/1674-1056/add7ad

Abstract ( 147 )

HTML ( 0 )

PDF (5854KB) ( 245 )

The interplay between 2$a_{0}\times2a_{0}$ charge density wave (CDW), nematicity and superconductivity in $A$V$_{3}$Sb$_{5}$ ($A = {\rm K}$, Rb, Cs) compounds gives rise to a rich landscape of intriguing physical phenomena. In addition to the 2$a_{0}\times2a_{0}$ CDW, a unidirectional 4$a_{0}$ stripe CDW is also observed on the Sb surface of RbV$_{3}$Sb$_{5}$ and CsV$_{3}$Sb$_{5}$. However, reports of stripe-like CDWs in KV$_{3}$Sb$_{5}$ have been limited. Here, we report the first observation of a long-range unidirectional stripe order with a $6a_{0}$ modulation period on the Sb surface of KV$_{3}$Sb$_{5}$, coexisting with the $2a_{0} \times 2a_{0}$ CDW. Notably, the intensity of the $6a_{0}$ stripes in STM topographies exhibits pronounced contrast reversal between opposite bias voltages. Additionally, the wave vector of the $6a_{0}$ modulation shows no energy-dependent dispersion, confirming its CDW origin. Furthermore, the $6a_{0}$ CDW is robust under a 7 T out-of-plane magnetic field and persists over a temperature range from 215 mK to 720 mK. These results provide compelling evidence for the emergence of a long-range unidirectional CDW in KV$_{3}$Sb$_{5}$.

Nontrivial Fermi surface topology in kagome superconductor CsTi₃Bi₅ revealed by de Haas-van Alphen oscillation

Yuhang Zhang(张宇航), Xinwei Yi(易鑫伟), Zhen Zhao(赵振), Jiali Liu(刘家利), Aini Xu(胥艾妮), Dong Li(李栋), Zouyouwei Lu(鲁邹有为), Yue Liu(刘樾), Jihu Lu(卢佶虎), Hua Zhang(张华), Hui Chen(陈辉), Shiliang Li(李世亮), Ziyi Liu(刘子儀), Jinguang Cheng(程金光), Gang Su(苏刚), Haitao Yang(杨海涛), Xiaoli Dong(董晓莉), Hong-Jun Gao(高鸿钧), and Zhongxian Zhao(赵忠贤)

Chin. Phys. B, 2025, 34 (7): 077107. DOI: 10.1088/1674-1056/adc7f0

Abstract ( 209 )

HTML ( 0 )

PDF (1594KB) ( 167 )

The kagome lattice, naturally encompassing Dirac fermions, flat bands, and van Hove singularities, tends to intertwine exotic electronic states. Revealing the characteristics of its Fermi surface will help clarify the nature of the complex quantum phenomena in kagome material. Here we report the Fermi surface properties of the novel kagome metal CsTi$_{{3}}$Bi$_{{5}}$ by the de Haas-van Alphen oscillations. The observed oscillations are clear and consist of six principal frequencies ranging from 214 T to 1013 T. The angular dependence of the frequency implies a quasi-two-dimensional electronic structure. In addition, the geometry phase corresponding to 281 T, determined by direct Lifshitz-Kosevich formula fitting, yields a value close to $\pi $, which may indicate a band structure with nontrivial topological property. These results underscore the potential of CsTi$_{{3}}$Bi$_{{5}}$ as a promising platform to explore the interplay between topological order, electronic nematicity, and superconductivity.

Theoretical investigation of potential superconductivity in Sr-doped La₃Ni₂O₇ at ambient pressure

Lei Shi(石磊), Ying Luo(罗颖), Wei Wu(吴为), and Yunwei Zhang(张云蔚)

Chin. Phys. B, 2025, 34 (7): 077403. DOI: 10.1088/1674-1056/add1bd

Abstract ( 127 )

HTML ( 0 )

PDF (2279KB) ( 96 )

The recent discovery of pressure-induced superconductivity in La$_{3}$Ni$_{2}$O$_{7}$ has established a novel platform for studying unconventional superconductors. However, achieving superconductivity in this system currently requires relatively high pressures. In this study, we propose a chemical pressure strategy via Sr substitution to stabilize high-$T_{\rm c}$ superconductivity in La$_{3}$Ni$_{2}$O$_{7}$ under ambient conditions. Using density functional theory (DFT) calculations, we systematically investigate the structural and electronic properties of Sr-doped La$_{3-x}$Sr$_{x}$Ni$_{2}$O$_{7}$ ($x= 0.25$, 0.5, 1) at ambient pressure and identify two dynamically stable phases: La$_{2.5}$Sr$_{0.5}$Ni$_{2}$O$_{7}$ and La$_{2}$SrNi$_{2}$O$_{7}$. Our calculations reveal that both phases exhibit metallization of the $\sigma $-bonding bands dominated by Ni-d$_{z^2}$ orbitals - a key feature associated with high-$T_{\rm c} $ superconductivity, as reported in the high-pressure phase of La$_{3}$Ni$_{2}$O$_{7}$. Further analysis using tight-binding models shows that the key hopping parameters in La$_{2.5}$Sr$_{0.5}$Ni$_{2}$O$_{7}$ and La$_{2}$SrNi$_{2}$O$_{7}$ closely resemble those of La$_{3}$Ni$_{2}$O$_{7}$ under high pressure, indicating that strong super-exchange interactions between interlayer Ni-$d_{z^2}$ orbitals are preserved. These findings suggest that the doped phases may provide a promising platform for exploring superconductivity, which requires further experimental validation.

State-selective single- and double-electron capture in collisions of low-energy S⁵⁺ ions with helium

Yixin Fan(樊依鑫), Dadi Xing(邢大地), Shucheng Cui(崔述成), Xiaoxia Wang(王小霞), Junxia Ran(冉俊霞), Kaizhao Lin(林楷钊), Xubin Zhu(朱旭斌), Dongmei Zhao(赵冬梅), Dalong Guo(郭大龙), Yong Gao(高永), Shaofeng Zhang(张少锋), Xiaolong Zhu(朱小龙), and Xinwen Ma(马新文)

Chin. Phys. B, 2025, 34 (7): 073402. DOI: 10.1088/1674-1056/adcb9a

Abstract ( 197 )

HTML ( 0 )

PDF (1206KB) ( 59 )

State-selective single- and double-electron capture processes in collisions of S$^{5+}$ ions with helium at energies ranging from 50.8 keV to 100 keV were investigated using cold target recoil ion momentum spectroscopy (COLTRIMS). $Q$-value spectra and projectile scattering angle distributions were obtained. For single-electron capture, single electron capture into $n = 3$ states of the projectile ion is dominant. As the projectile energy increases, the contribution of single electron capture into $n = 4$ states is observed. Experimental relative cross-sections for single-electron capture into different projectile final states were compared with theoretical predictions based on the molecular orbital close-coupling (MOCC) method. In double-electron capture, two-electron populating into the 3s$^2$3p and 3s3p$^2$ states of projectile dominates. The reaction window calculated from the classical molecular Coulombic barrier model can qualitatively explain the experimental results. The scattering angle distribution of the multi-peak structure of the double-electron capture process is observed. The database is openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00233.

High-sensitivity spectroscopic measurements under pulsed high magnetic field

Zheng Wang(王政), Yichun Pan(潘议淳), Guangran Yang(杨光冉), Wei Xie(谢微), and Weihang Zhou(周伟航)

Chin. Phys. B, 2025, 34 (7): 070701. DOI: 10.1088/1674-1056/adce95

Abstract ( 214 )

HTML ( 0 )

PDF (1016KB) ( 106 )

Pulsed magnet technology is the only way to generate ultra-strong magnetic fields higher than 45 T so far. However, the inherently fast-changing field strength (typically on the order of 1000 T/s) poses significant challenges for spectroscopic measurements which rely on time integration of signals to improve spectral qualities. In this work, we report high-sensitivity spectroscopic measurements under pulsed high magnetic fields employing the long flat-top pulsed magnetic field technique. By means of a multiple-capacitor power supply, we were able to generate pulsed high magnetic fields with controllable flat-top pulse width and field stabilities. By synchronizing spectroscopic measurements with the waveform of the flat-top magnetic field, the integration time of each spectrum can be increased by up to 100 times compared with that of the conventional spectroscopic measurements under pulsed magnetic fields, thus enabling high-sensitivity spectroscopic measurements under ultra-strong pulsed magnetic fields. These findings promise an efficient way to significantly improve the performance and extend the application of optical measurements under pulsed high magnetic fields.

Spin-based magnetic detection of optically trapped single cell in microfluidic channel

Jun Yin(殷俊), Sanyou Chen(陈三友), Yihao Yan(燕一皓), Mengqi Wang(王孟祺), Ya Wang(王亚), Yiheng Lin(林毅恒), Qi Zhang(张琪), and Fazhan Shi(石发展)

Chin. Phys. B, 2025, 34 (7): 070704. DOI: 10.1088/1674-1056/adde38

Abstract ( 143 )

HTML ( 4 )

PDF (1189KB) ( 61 )

Combining optical tweezers with fluorescence microscopy is a powerful tool for single-cell analysis, playing a pivotal role in disease diagnosis, cell sorting, and the investigation of cellular dynamics. However, fluorescence detection faces challenges such as blinking, photobleaching and autofluorescence in biotissues. To address these limitations, we developed a magnetic detection strategy by integrating quantum magnetometry using nitrogen-vacancy centers into optical tweezers, demonstrating precise trapping and manipulation of individual cells in microfluidic environment. We detected a magnetic signal of 89 μT from a single cell labeled with magnetic nanoparticles, compared to a noise floor of 3.9 μT observed in unlabeled cells. This platform provides a promising approach for high-precision single-cell analysis and holds significant potential for probing cellular activities within biological microenvironments.

Progressive quantum algorithm for maximum independent set with quantum alternating operator ansatz

Xiao-Hui Ni(倪晓慧), Ling-Xiao Li(李凌霄), Yan-Qi Song(宋燕琪), Zheng-Ping Jin(金正平), Su-Juan Qin(秦素娟), and Fei Gao(高飞)

Chin. Phys. B, 2025, 34 (7): 070304. DOI: 10.1088/1674-1056/addd83

Abstract ( 152 )

HTML ( 0 )

PDF (1456KB) ( 219 )

The quantum alternating operator ansatz algorithm (QAOA+) is widely used for constrained combinatorial optimization problems (CCOPs) due to its ability to construct feasible solution spaces. In this paper, we propose a progressive quantum algorithm (PQA) to reduce qubit requirements for QAOA+ in solving the maximum independent set (MIS) problem. PQA iteratively constructs a subgraph likely to include the MIS solution of the original graph and solves the problem on it to approximate the global solution. Specifically, PQA starts with a small-scale subgraph and progressively expands its graph size utilizing heuristic expansion strategies. After each expansion, PQA solves the MIS problem on the newly generated subgraph using QAOA+. In each run, PQA repeats the expansion and solving process until a predefined stopping condition is reached. Simulation results show that PQA achieves an approximation ratio of 0.95 using only $5.57%$ ($2.17%$) of the qubits and $17.59%$ ($6.43%$) of the runtime compared with directly solving the original problem with QAOA+ on Erdös-Rényi (3-regular) graphs, highlighting the efficiency and scalability of PQA.

Bayesian phase difference estimation based on single-photon projective measurement ^Hot! Suggested by editors

Xu-Hao Yu(余旭豪), Ying Wei(韦颖), Ran Yang(杨然), Wen-Hui Song(宋文慧), Yingning Miao(缪应宁), Wei Zhou(周唯), Xinhui Li(李新慧), Xiaoqin Gao(高小钦), Yan-Xiao Gong(龚彦晓), and Shi-Ning Zhu(祝世宁)

Chin. Phys. B, 2025, 34 (7): 070305. DOI: 10.1088/1674-1056/adde33

Abstract ( 485 )

HTML ( 3 )

PDF (1104KB) ( 385 )

The estimation of quantum phase differences plays an important role in quantum simulation and quantum computation, yet existing quantum phase estimation algorithms face critical limitations in noisy intermediate-scale quantum (NISQ) devices due to their excessive depth and circuit complexity. We demonstrate a high-precision phase difference estimation protocol based on the Bayesian phase difference estimation algorithm and single-photon projective measurement. The iterative framework of the algorithm, combined with the independence from controlled unitary operations, inherently mitigates circuit depth and complexity limitations. Through an experimental realization on the photonic system, we demonstrate high-precision estimation of diverse phase differences, showing root-mean-square errors (RMSE) below the standard quantum limit $\mathcal{O}(1/\sqrt{N})$ and reaching the Heisenberg scaling $\mathcal{O}(1/N)$ after a certain number of iterations. Our scheme provides a critical advantage in quantum resource-constrained scenarios, and advances practical implementations of quantum information tasks under realistic hardware constraints.

Effect of gold doping on relativistic electron beam transport in high-density plasma

Zi-Yan Zhang(张子彦) and Wei-Min Wang(王伟民)

Chin. Phys. B, 2025, 34 (7): 075201. DOI: 10.1088/1674-1056/add4df

Abstract ( 140 )

HTML ( 0 )

PDF (886KB) ( 69 )

We investigate the influence of gold doping on the transport range of a relativistic electron beam in high-density deuterium-tritium (DT) fuel, which could be encountered in the double-cone ignition laser fusion. We develop the stopping power model to include gold doping and then analyze the influence of Coulomb collision and bremsstrahlung on the electron transport range with different gold doping ratios, consistent with the Geant4 simulations. When the gold doping ratio increases from 0.5% to 30%, the transport range of a 10 MeV electron beam is decreased by 9.6% and 18.5% via the bremsstrahlung. For the 1 MeV beam, the decrease of the range becomes 0.7% and 1.0%. We also investigate the transverse broadening of the electron beam and radiated photon energy reabsorption in a spherical target. When the gold doping ratio is 2% and the beam energy is increased from 1 MeV to 5 MeV, the bremsstrahlung photons cover 2.6% to 10.3% of the total beam energy. Meanwhile, the reabsorbed photon energy is reduced from 31.6% to 8.9%.

Atomic insights into topochemical fluorination and strong octahedral tilt in La₂CoO₄ ^Hot! Suggested by editors

Yuzhou He(何玉洲), Ting Lin(林挺), Shiyu Wang(王诗雨), Ang Gao(高昂), Ziang Meng(孟子昂), Tianping Ying(应天平), Zhiqi Liu(刘知琪), Lin Gu(谷林), Qinghua Zhang(张庆华), and Binghui Ge(葛炳辉)

Chin. Phys. B, 2025, 34 (7): 076102. DOI: 10.1088/1674-1056/adda0a

Abstract ( 241 )

HTML ( 1 )

PDF (2007KB) ( 271 )

Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine. However, the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear. Here we investigated the atomic-scale O/F exchange in La$_{2}$CoO$_{4}$ and quantified the lattice distortion of three ordered structures: La$_{2}$CoO$_{3.5}$F, La$_{2}$CoO$_{3}$F$_{2}$, and La$_{2}$CoO$_{2.5}$F$_{3}$ by utilizing aberration-corrected electron microscopy. Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites. We revealed that apical F ions induce significant octahedral tilting from 178$^\circ$ to 165$^\circ$, linearly proportional to the occupancy rate; and cause the obvious change in the fine structure O $K$ edge, meanwhile apical O is exchanged into interstitial sites. The strong octahedral tilt leads to the in-plane elongation of the [CoO$_{4}$F$_{2}$] octahedra. These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.

Characterization of antisite defects and in-gap states in antiferromagnetic MnSb₂Te₄ ^Hot! Suggested by editors

Junming Zhang(张峻铭), Ming Xi(席明), Yuchong Zhang(张羽翀), Hang Li(李航), Jiali Zhao(赵佳丽), Hechang Lei(雷和畅), Zhongxu Wei(魏忠旭), and Tian Qian(钱天)

Chin. Phys. B, 2025, 34 (7): 076801. DOI: 10.1088/1674-1056/adcea3

Abstract ( 258 )

HTML ( 3 )

PDF (1486KB) ( 207 )

Intrinsic magnetic topological insulators have been reported to exhibit novel physical phenomena such as the quantum anomalous Hall effect and axion insulator states, demonstrating potential for applications in spintronics and topological quantum computing. Here we perform low-temperature scanning tunneling microscopy (STM) investigations of the antiferromagnetic ground state of MnSb$_{2}$Te$_{4}$, a predicted magnetic topological insulator isostructural with MnBi$_{2}$Te$_{4}$. We visualize the hexagonal Te-terminated surface of MnSb$_{2}$Te$_{4}$ and identify two distinct defects originating from different antisite substitutions. Notably, we identify an in-gap state above the Fermi energy where the tunneling spectrum exhibits a negative differential conductance behavior. This electronic state can be modulated by external electric and magnetic fields, suggesting effective pathways for electronic state manipulation. Spin-resolved STM measurements further reveal additional magnetic resonance peaks associated with Mn antisite defects. Our results provide novel insights into the investigation of magnetic topological insulators and demonstrate a promising approach to modulate the localized electronic states.

Momentum-dependent anisotropy of the charge density wave gap in quasi-1D ZrTe_3-xSe_x (x = 0.015) ^Hot! Suggested by editors

Renjie Zhang(张任杰), Yudong Hu(胡裕栋), Yiwei Cheng(程以伟), Yigui Zhong(钟益桂), Xuezhi Chen(陈学智), Junqin Li(李俊琴), Kozo Okazaki, Yaobo Huang(黄耀波), Tian Shang(商恬), Shifeng Jin(金士锋), Baiqing Lv(吕佰晴), and Hong Ding(丁洪)

Chin. Phys. B, 2025, 34 (7): 077106. DOI: 10.1088/1674-1056/addcc5

Abstract ( 227 )

HTML ( 1 )

PDF (2267KB) ( 234 )

The charge density wave (CDW) state is a ubiquitous ordered phase in condensed matter systems, characterized by a periodic modulation of the electronic charge density. In many CDW materials, superconductivity (SC) emerges in close proximity to, or coexists with, the CDW phase, offering a valuable platform to explore the interplay between these two competing orders. The ZrTe$_{3-x}$Se$_x$ family provides an ideal system for investigating this interplay, as both CDW-dominated and superconductivity-dominated end members have been well studied, while the intermediate compositions remain largely unexplored. In this study, we employ high-resolution angle-resolved photoemission spectroscopy (ARPES) to systematically investigate the band structure and CDW gap in Se-doped ZrTe$_{3-x}$Se$_{x}$ ($x= 0.015$), a prototypical system exhibiting the coexistence of CDW and superconductivity phases. Detailed analysis of the band structure across the Brillouin zone reveals highly momentum-dependent, anisotropic CDW gaps. Quasi-2D Fermi surface centered at $\bar{\varGamma }$ exhibits the absence of CDW gap, while on quasi-1D Fermi surface along the Brillouin zone boundary, there is also a highly anisotropic distribution of CDW gap. The gap is zero at $\bar{B}$, while reaching its maximum at a nesting vector consistent with the bulk CDW modulation. These results provide direct evidence that quasi-1D Fermi surface nesting is the primary driving force behind CDW formation in this compound. Notably, our measurements reveal a strongly suppressed density of state around $E_{\rm F}$ even out of CDW gap and absence of band folding induced by Fermi surface nesting. This observation suggests that selenium doping enhances fluctuations of the CDW order parameter, thereby weakening the long-range CDW coherence. Such enhanced fluctuations are likely to facilitate SC pairing, contributing to the observed increase in the SC transition temperature of the doped samples. Our findings not only provide comprehensive understanding of the CDW state in the ZrTe$_{3-x}$Se$_{x}$ family but also demonstrate that chemical doping provides an effective route to tune the competition between CDW and superconductivity.

In-plane negative magnetoresistance and quantum oscillations in van der Waals antiferromagnet DyTe₃ ^Hot! Suggested by editors

Qi Qi(齐琦), Senhao Lv(吕森浩), Ke Zhu(祝轲), Yaofeng Xie(谢耀锋), Guojing Hu(胡国静), Zhen Zhao(赵振), Guoyu Xian(冼国裕), Yechao Han(韩烨超), Yang Yang(杨洋), Lihong Bao(鲍丽宏), Xiao Lin(林晓), Hui Guo(郭辉), Haitao Yang(杨海涛), and Hong-Jun Gao(高鸿钧)

Chin. Phys. B, 2025, 34 (7): 077305. DOI: 10.1088/1674-1056/adcc87

Abstract ( 261 )

HTML ( 0 )

PDF (1455KB) ( 175 )

Two-dimensional van der Waals (vdW) magnetic materials, characterized by their tunable magnetism, spin transport properties, and remarkable quantum effects, provide significant promise for the development of efficient, low-power spintronic devices. Intriguingly, the rare earth tritelluride ($R$Te$_3$) materials have attracted great attention due to their unique magnetic structure, exotic electronic properties, multiple charge density wave (CDW), and superconductivity under pressure. Here, we report the successful synthesis of high-quality DyTe$_{3}$ single crystals using a self-flux method. DyTe$_{3}$ shows an antiferromagnetic transition at 4.5 K and demonstrates the magnetic field-induced ferromagnetism. The high-quality DyTe$_{3}$ single crystal demonstrates outstanding transport properties, featuring a high carrier mobility of approximately 1.4$\times10^{4}$ cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1}$ and large linear magnetoresistance of 1300%. Furthermore, distinct Shubnikov-de Haas (SdH) oscillations are observed in DyTe$_{3}$, revealing a small Fermi pocket and an effective mass of 0.24 $m_{\rm e}$. Remarkably, the unconventional in-plane negative magnetoresistances appear along the $a$-axis below 2 T and $c$-axis until 9 T from 2 K to 17 K, which are attributed to the complex helimagnetic structures caused by CDW coupling and weak single-ion anisotropy. Our findings offer a significant platform for understanding the complex magnetoresistance behavior and quantum transport effects in $R$Te$_{3}$-type materials, holding great promise for advancing applications in electronic and spintronic devices.

Magnetotransport properties of large-scale PtTe₂ Dirac semimetal films grown by pulsed laser deposition ^Hot! Suggested by editors

Zhongqiang Chen(陈中强), Zhe Wang(王喆), Kankan Xu(徐侃侃), Xu Zhang(张旭), Ruijie Xu(徐睿劼), and Xuefeng Wang(王学锋)

Chin. Phys. B, 2025, 34 (7): 077401. DOI: 10.1088/1674-1056/adcf8c

Abstract ( 220 )

HTML ( 0 )

PDF (1703KB) ( 189 )

Type-II Dirac semimetal PtTe$_{2}$ is a promising candidate for various electronic device applications due to its high carrier mobility, high conductivity, and air stability. In this work, we report on the growth of large-scale PtTe$_{2}$ films by the pulsed laser deposition (PLD) and the comparison of the magnetotransport properties with the PtTe$_{2}$ films grown by the chemical vapor deposition (CVD). The low-temperature Hall curves of the PLD-grown films exhibit a linear behavior, in contrast with the nonlinear characteristic of the Hall behavior observed in CVD-grown films, in which a defect gradient is introduced. Meanwhile, both PtTe$_{2}$ films show weak antilocalization at low temperatures, which is attributed to the strong spin-orbit coupling.

Doping evolution of nodal electron dynamics in trilayer cuprate superconductor Bi₂Sr₂Ca₂Cu₃O_10+δ revealed by laser-based angle-resolved photoemission spectroscopy ^Hot!

Hao Chen(陈浩), Jumin Shi(史聚民), Xiangyu Luo(罗翔宇), Yinghao Li(李颖昊), Yiwen Chen(陈逸雯), Chaohui Yin(殷超辉), Yingjie Shu(束英杰), Jiuxiang Zhang(张九相), Taimin Miao(苗泰民), Bo Liang(梁波), Wenpei Zhu(朱文培), Neng Cai(蔡能), Xiaolin Ren(任晓琳), Chengtian Lin(林成天), Shenjin Zhang(张申金), Zhimin Wang(王志敏), Fengfeng Zhang(张丰丰), Feng Yang(杨峰), Qinjun Peng(彭钦军), Zuyan Xu(许祖彦), Guodong Liu(刘国东), Hanqing Mao(毛寒青), Xintong Li(李昕彤), Lin Zhao(赵林), and X. J. Zhou(周兴江)

Chin. Phys. B, 2025, 34 (7): 077404. DOI: 10.1088/1674-1056/addcc6

Abstract ( 322 )

HTML ( 9 )

PDF (1554KB) ( 270 )

The doping evolution of the nodal electron dynamics in the trilayer cuprate superconductor $\mathrm{Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+\delta}}$ (Bi2223) is investigated using high-resolution laser-based angle-resolved photoemission spectroscopy (ARPES). Bi2223 single crystals with different doping levels are prepared by controlled annealing, which cover the underdoped, optimally-doped and overdoped regions. The electronic phase diagram of Bi2223 is established which describes the $T_{\rm c}$ dependence on the sample doping level. The doping dependence of the nodal Fermi momentum for the outer (OP) and inner (IP) CuO$_2$ planes is determined. Charge distribution imbalance between the OP and IP CuO$_2$ planes is quantified, showing enhanced disparity with increasing doping. Nodal band dispersions demonstrate a prominent kink at $\sim94$ meV in the IP band, attributed to the unique Cu coordination in the IP plane, while a weaker $\sim60$ meV kink is observed in the OP band. The nodal Fermi velocity of both OP and IP bands is nearly constant at $\sim1.62$ eV$\cdot$Å independent of doping. These results provide important information to understand the origin of high $T_{\rm c}$ and superconductivity mechanism in high temperature cuprate superconductors.

Prolongation structure and Darboux transformation of nonlinear mixed gas equations

Lixiu Wang(王立秀) and Yangjie Jia(加羊杰)

Chin. Phys. B, 2025, 34 (7): 070201. DOI: 10.1088/1674-1056/adcdf1

Abstract ( 141 )

HTML ( 0 )

PDF (627KB) ( 51 )

The widespread popularization and application of laser technology have provided a powerful tool for a deeper understanding of the material world and given birth to several emerging research fields. This study mainly focuses on the following three key aspects. First, the classical ensemble method is adopted to conduct a comprehensive and in-depth analysis of two-dimensional (2D) matter-wave pulses in Bose-Fermi mixed gases (including linear and nonlinear pulses). Second, under the strict constraints of unitary systems, a coupled $\mathrm{KdV}$ equation is successfully derived, and the prolongation structure theory is skillfully used to carry out detailed calculations and analyses on this equation. Thus, the prolongation algebra of this equation is accurately determined, and the corresponding $\mathrm{Lax}$ pair is rigorously derived. Finally, based on the carefully obtained $\mathrm{Lax}$ pair from the prolongation structure theory, the soliton solutions of this equation are further analyzed in depth, and intuitive images of each soliton solution are carefully drawn. This lays a solid foundation for subsequent detailed research on these soliton characteristics and provides great convenience.

An N-breather solution and hybrid solutions of rogue wave and breather for complex mKdV equation

Wenjing Hu(胡文静) and Hasi Gegen(葛根哈斯)

Chin. Phys. B, 2025, 34 (7): 070202. DOI: 10.1088/1674-1056/adcdef

Abstract ( 180 )

HTML ( 0 )

PDF (4801KB) ( 61 )

A compact Grammian form for N-breather solution to the complex mKdV equation is derived using the bilinear Kadomtsev-Petviashvili hierarchy reduction method. The propagation trajectory, period, maximum points, and peak value of the 1-breather solution are calculated. Additionally, through the asymptotic analysis of 2-breather solution, we show that two breathers undergo an elastic collision. By applying the generalized long-wave limit method, the fundamental and second-order rogue wave solutions for the complex mKdV equation are obtained from the 1-breather and 2-breather solutions, respectively. We also construct the hybrid solution of a breather and a fundamental rogue wave for the complex mKdV equation from the 2-breather solution. Furthermore, the hybrid solution of two breathers and a fundamental rogue wave as well as the hybrid solution of a breather and a second-order rogue wave for the complex mKdV equation are derived from the 3-breather solution via the generalized long-wave limit method. By controlling the phase parameters of breathers, the diverse phenomena of interaction between the breathers and the rogue waves are demonstrated.

Non-quantized Zak phases, PT/APT symmetry transitions, and doubly degenerate exceptional points in a non-Hermitian spin-orbit coupled SSH model

Jun-Xing Huo(霍俊行), Jian Li(李健), Qing-Xu Li(李清旭), and Jia-Ji Zhu(朱家骥)

Chin. Phys. B, 2025, 34 (7): 070301. DOI: 10.1088/1674-1056/adc7f3

Abstract ( 218 )

HTML ( 0 )

PDF (1781KB) ( 58 )

We theoretically investigate a one-dimensional Su-Schrieffer-Heeger (SSH) model with spin-orbit coupling (SOC) and sublattice-dependent gain and loss. As the gain and loss increase, the system transitions from a parity-time (${\rm PT}$) symmetric phase to a parity-time and anti-parity-time (${\rm PT\&APT}$) symmetry-breaking phase, and finally to an anti-parity-time (${\rm APT}$) symmetric phase. Notably, when the intracell and intercell hopping, intracell and intercell SOC parameters are all equal to half the gain-loss parameter, the model exhibits a doubly degenerate exceptional point (EP). When the SOC is equal for intracell and intercell interactions, a stronger hopping mechanism within cells compared to that between cells results in an increase in SOC that transitions the Zak phase from zero to a non-quantized value, eventually arriving at one. In contrast, a reduction in the strength of intracell hopping leads the Zak phase to transition from two to a non-quantized value, eventually arriving at one. If the intracell and intercell SOC are not aligned, altering these couplings leads to a shift in the Zak phase from two to a non-quantized level, then to one, re-entering the non-quantized region, and eventually arriving at zero. We suggest a practical experimental setup for our model that can be implemented using electrical circuits.

Domain adaptation method inspired by quantum convolutional neural network

Chunhui Wu(武春辉), Junhao Pei(裴骏豪), Yihua Wu(吴逸华), Anqi Zhang(张安琪), and Shengmei Zhao(赵生妹)

Chin. Phys. B, 2025, 34 (7): 070302. DOI: 10.1088/1674-1056/adc7ed

Abstract ( 167 )

HTML ( 0 )

PDF (1995KB) ( 93 )

Quantum machine learning is an important application of quantum computing in the era of noisy intermediate-scale quantum devices. Domain adaptation (DA) is an effective method for addressing the distribution discrepancy problem between the training data and the real data when the neural network model is deployed. In this paper, we propose a variational quantum domain adaptation method inspired by the quantum convolutional neural network, named variational quantum domain adaptation (VQDA). The data are first uploaded by a 'quantum coding module', then the feature information is extracted by several 'quantum convolution layers' and 'quantum pooling layers', which is named `Feature Extractor'. Subsequently, the labels and the domains of the samples are obtained by the 'quantum fully connected layer'. With a gradient reversal module, the trained 'Feature Extractor' can extract the features that cannot be distinguished from the source and target domains. The simulations on the local computer and IBM Quantum Experience (IBM Q) platform by Qiskit show the effectiveness of the proposed method. The results show that VQDA (with 8 quantum bits) has 91.46% average classification accuracy for DA task between MNIST$\rightarrow$USPS (USPS$\rightarrow$ MNIST), achieves 91.16% average classification accuracy for gray-scale and color images (with 10 quantum bits), and has 69.25% average classification accuracy on the DA task for color images (also with 10 quantum bits). VQDA achieves a 9.14% improvement in average classification accuracy compared to its corresponding classical domain adaptation method with the same parameter scale for different DA tasks. Simultaneously, the parameters scale is reduced to 43% by using VQDA when both quantum and classical DA methods have similar classification accuracies.

Quantum-enhanced time-of-arrival measuring method based on partially entangled state

Peng-Xian Li(李芃鲜), Lu-Ping Xu(许录平), Gui-Ting Hu(胡桂廷), and Wen-Long Gao(高文珑)

Chin. Phys. B, 2025, 34 (7): 070303. DOI: 10.1088/1674-1056/adc7ee

Abstract ( 135 )

HTML ( 0 )

PDF (2363KB) ( 275 )

We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequency-entangled states. By establishing the fundamental relationship between the degree of entanglement, channel transmission efficiency and measurement precision, we demonstrate superclassical timing resolution in both lossless and lossy regimes. Theoretical analysis and numerical simulations reveal that, under a lossless channel, the precision gain increases with the degree of entanglement, approaching the Heisenberg limit. Importantly, in lossy channels, the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement. For transmission efficiencies above 50%, the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized. Moreover, by optimizing intra-group and inter-group covariances in the multi-structured entangled state, we achieve substantial precision gains even at low transmission efficiencies ($\sim 30%$), demonstrating its robustness against loss. This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation. Future implementation could extend to satellite-based quantum positioning, remote sensing, quantum illumination, and other fields that require high-precision ranging in lossy environments. The protocol establishes a universal framework for loss-tolerant quantum metrology, advancing the practical deployment of quantum-enhanced sensing in real-world applications.

Complexity dynamics analysis of a dual-channel green supply chain with government intervention and cap-and-trade regulation

Yuhao Zhang(张玉豪), Lin Huang(黄林), and Man Yang(杨满)

Chin. Phys. B, 2025, 34 (7): 070501. DOI: 10.1088/1674-1056/adca9c

Abstract ( 131 )

HTML ( 0 )

PDF (6692KB) ( 39 )

This paper studies a dual-channel green supply chain consisting of one manufacturer and one retailer in presence of government green subsidy and cap-and-trade regulation policies. We first develop and analyze a single-period Stackelberg and a multi-period dynamic Stackelberg game models respectively with consistent pricing strategy. Subsequently, we extend these two game models by utilizing an inconsistent pricing strategy. The optimal solutions for the single-period Stackelberg game models in both scenarios are derived by means of the backward induction approach. Moreover, the existence and local asymptotic stability of the equilibrium points of the multi-period dynamic Stackelberg game models are examined, and the complex dynamics of chain members' long-term strategy evolution are investigated through chaos theory and numerical simulation. Additionally, the variable feedback control and time-delay feedback control method are utilized to eliminate system chaos respectively. The results indicate that (i) The excessive fast adjustment speeds by the manufacturer have a destabilizing effect on the stability of the Nash equilibrium point. (ii) The manufacturer's profits are improved with green subsidy degree increases, while its impact on the retailer's profits depends on certain parameter conditions, and the high carbon trading price is disadvantage to both chain members. (iii) The system's motion can transition from a steady state to a chaotic period through period-doubling or Neimark-Sacker bifurcations. (iv) The system's steady state is conducive to the manufacturer, while the retailer can benefit from the system's periodic cycles. Furthermore, both chain members' profits are declined when the system becomes chaotic. Lastly, the variable feedback and time-delay feedback control method can effectively eliminate system chaos.

Optimal synchronization of higher-order Kuramoto model on hypergraphs

Chong-Yang Wang(王重阳), Bi-Yun Ji(季碧芸), and Linyuan Lü(吕琳媛)

Chin. Phys. B, 2025, 34 (7): 070502. DOI: 10.1088/1674-1056/adcded

Abstract ( 145 )

HTML ( 0 )

PDF (874KB) ( 253 )

Complex networks play a crucial role in the study of collective behavior, encompassing the analysis of dynamical properties and network topology. In real-world systems, higher-order interactions among multiple entities are widespread and significantly influence collective dynamics. Here, we extend the synchronization alignment function framework to hypergraphs of arbitrary order by leveraging the multi-order Laplacian matrix to encode higher-order interactions. Our findings reveal that the upper bound of synchronous behavior is determined by the maximum eigenvalue of the multi-order Laplacian matrix. Furthermore, we decompose the contribution of each hyperedge to this eigenvalue and utilize it as a basis for designing an eigenvalue-based topology modification algorithm. This algorithm effectively enhances the upper bound of synchronous behavior without altering the total number of higher-order interactions. Our study provides new insights into dynamical optimization and topology tuning in hypergraphs, advancing the understanding of the interplay between higher-order interactions and collective dynamics.

Effects of noise on synchronization in simplicial complexes

Linying Xiang(项林英), Shuwei Yao(姚姝玮), Yining Chen(陈艺宁), Ruitong Yan(闫锐桐), and Ruya Xia(夏儒雅)

Chin. Phys. B, 2025, 34 (7): 070503. DOI: 10.1088/1674-1056/adc7ef

Abstract ( 153 )

HTML ( 0 )

PDF (3180KB) ( 51 )

This paper explores the synchronization of stochastic simplicial complexes with noise, modeled by stochastic differential equations of Itô type. It establishes the relationship between synchronization and individual dynamics, higher-order structures, coupling strengths, and noise. In particular, this study delves into the role of multi-body interactions, particularly focusing on the influence of higher-order simplicial structures on the overall synchronization behavior. Furthermore, the effects of noise on synchronizability in the stochastic simplicial complex are thoroughly examined. The obtained results indicate that the effects of noise on the synchronizability vary with the manner in which noise propagates. The presence of noise can regulate the synchronization pattern of the simplicial complex, transforming the unstable state into a stable state, and vice versa. These findings offer valuable insights and a theoretical foundation for improving the performance of real-world networks, such as communication networks, biological systems, and social networks, where noise is often inevitable.

On the topographic Rossby solitary waves via physical-informed neural networks

Wenxu Liu(刘文绪), Ligeyan Dao(道力格艳), and Ruigang Zhang(张瑞岗)

Chin. Phys. B, 2025, 34 (7): 070504. DOI: 10.1088/1674-1056/adc7f1

Abstract ( 165 )

HTML ( 1 )

PDF (3248KB) ( 20 )

In the generation and propagation of nonlinear Rossby solitary waves within the atmosphere and ocean, topography occupies a pivotal role. This paper focuses on elucidating the impact of topography on such Rossby solitary waves. Utilizing the perturbation expansion method and spatialtemporal transformations, we derive the Korteweg-de Vries and modified Korteweg-de Vries equation (Gardner equation) governing the amplitude of nonlinear Rossby waves. A fundamental issue addressed herein is a Sturm-Liouville-type ordinary differential equation characterized by variable coefficients and fixed boundary conditions. To numerically solve the derived Korteweg-de Vries and modified Korteweg-de Vries equations, we employ a physical-informed neural network. Both qualitative and quantitative analyses are conducted to discuss the influences of topography and $\beta$ effects, respectively.

An enhanced fingerprint template protection scheme based on four-dimensional superchaotic system and dynamic DNA coding

Baiqiang Hu(胡百强), Jiahui Liu(刘嘉辉), and Zhe Liu(刘喆)

Chin. Phys. B, 2025, 34 (7): 070505. DOI: 10.1088/1674-1056/adca9f

Abstract ( 152 )

HTML ( 0 )

PDF (2208KB) ( 108 )

With the rapid development of Internet of things technology, the efficiency of data transmission between devices has been significantly improved. However, the open network environment also poses serious security risks. This paper proposes an innovative fingerprint template protection scheme, which generates key streams through an improved four-dimensional superchaotic system (4CSCS), uses the space-filling property of Hilbert curves to achieve pixel scrambling, and introduces dynamic DNA encoding to improve encryption. Experimental results show that this scheme has a large key space $2^{528}$, encrypts image information entropy of more than 7.9970, and shows excellent performance in defending against statistical attacks and differential attacks. Compared with existing methods, this scheme has significant advantages in terms of encryption performance and security, and provides a reliable protection mechanism for fingerprint authentication systems in the Internet of things environment.

Flux trapping behavior in a joint-less closed-loop 2G-HTS coil under multi-pulse magnetic field excitation

Hao Dong(董浩), Daxing Huang(黄大兴), Hao Yu(于昊), Hongwei Gu(古宏伟), and Fazhu Ding(丁发柱)

Chin. Phys. B, 2025, 34 (7): 070702. DOI: 10.1088/1674-1056/adcdf0

Abstract ( 137 )

HTML ( 0 )

PDF (1326KB) ( 36 )

Second-generation high-temperature superconducting (2G-HTS) magnets operating in persistent current mode (PCM) hold great promise for applications such as magnetic resonance imaging. The development of joint-less closed-loop magnets has effectively tackled the challenges of fabricating joints for REBCO tape. However, certain closed-loop magnets cannot utilize conventional persistent current switches (PCS) and instead require multi-pulse magnetization techniques. This study explores the effects of multi-pulse magnetic field excitation on the flux trapping behavior of a four-pancake coil (FPC). A detailed comparison of the effects of different pulse types and periods on the FPC reveals that the background magnetic field exceeds the critical magnetic field of the coil, thereby creating resistance in the superconducting loop. The critical magnetic field of the FPC is determined experimentally, and a reasonable speculation on the multi-pulse field excitation mechanism is presented.

Enhancement of thermal conductivity in diamond/Al composites through vacuum-pressure thermal diffusion sintering

Wenxia Zhang(张文霞), Weixia Shen(沈维霞), Chao Fang(房超), Ye Wang(王烨), Yuewen Zhang(张跃文), Liangchao Chen(陈良超), Qianqian Wang(王倩倩), Kenan Li(黎克楠), Biao Wan(万彪), and Zhuangfei Zhang(张壮飞)

Chin. Phys. B, 2025, 34 (7): 070703. DOI: 10.1088/1674-1056/adca9e

Abstract ( 172 )

HTML ( 1 )

PDF (1994KB) ( 54 )

Improving the thermal conductivity (TC) of diamond-metal composites has always been a significant challenge in the field of thermal management. In this paper, diamond/Al composites are systematically studied, and the influence of the holding time (10-120 min) on interface structure and TC is discussed. The results of this research show that long-term thermal diffusion sintering can achieve dense interfacial bonding in diamond/Al composites, enhancing their TC. Diamond/Al composites with 50 vol% of 900 μm diamond attain the highest TC value of 888.73 W$\cdot$m$^{-1}\cdot$K$^{-1}$ under sintering conditions of 650 $^\circ $C, 50 MPa, and 120 min - nearly 92% of the theoretical value predicted by the Maxwell model. This study establishes that high TC can be achieved through long-term thermal diffusion alone, without the need for complex diamond surface coating or substrate alloying.

Isotope shifts due to the 1s²2s ²S_1/2 → 1s²2p ²P_1/2,3/2 transitions of Li-like Th⁸⁷⁺ ions

Huqiang Lu(路虎强), Bingbing Li(李兵兵), Mingye Yang(杨明叶), Lin Dong(董霖), Yanmin Wang(王雁敏), Maijuan Li(李麦娟), Lei Wu(吴磊), Jiguang Li(李冀光), Jun Jiang(蒋军), Chenzhong Dong(董晨钟), and Denghong Zhang(张登红)

Chin. Phys. B, 2025, 34 (7): 073203. DOI: 10.1088/1674-1056/adcb21

Abstract ( 159 )

HTML ( 0 )

PDF (702KB) ( 96 )

The transition energies of the 1s$^22$s ${^2}$S$_{1/2}$ $\to$ 1s$^22$p $^{2}$P$_{1/2,3/2}$ transitions in Li-like Th${^{87+}}$ ions were calculated by combining the multi-configuration Dirac-Hartree-Fock (MCDHF) method with the model-quantum electrodynamics (model-QED) approach. The effects of electron correlation, Breit interaction, and QED effects were analyzed in detail. The isotope shifts, including the mass shifts and field shifts, due to the 2s ${^2}$S$_{1/2}$ $\to$ 2p $^{2}$P$_{1/2,3/2}$ transitions were then calculated using two different methods, namely, the MCDHF method and the finite-field method. The results show that these two methods are in excellent agreement.

Dual-species stimulated deceleration of MgF molecules with Rb atoms

Jin Wei(魏晋), Di Wu(吴迪), Chenyu Zu(祖晨宇), Yong Xia(夏勇), and Jianping Yin(印建平)

Chin. Phys. B, 2025, 34 (7): 073701. DOI: 10.1088/1674-1056/adcb1f

Abstract ( 164 )

HTML ( 0 )

PDF (1649KB) ( 13 )

We propose a scheme for dual-species deceleration and trapping of a cold atom-molecule mixture by a frequency chirping stimulated force. We study the stimulated force exerted on MgF and Rb using optical Bloch equations based on a direct numerical solution for the time-dependent density matrix. We analyze the relationship between the frequency chirping rate and the number of MgF molecules and Rb atoms. In addition, we study the dynamical process of molecular deceleration and the effect of transverse diffusion. Monte-Carlo simulations show that buffer-gas-cooled MgF and Rb beams, with initial velocities of 200 m/s and 130 m/s respectively, can be decelerated to less than 10 m/s. This is achieved with laser powers of as low as 357 mW for MgF and 10 mW for Rb per traveling wave. The rapid deceleration minimizes molecular loss due to transverse diffusion during the deceleration process. The estimated number of molecules that can be trapped in a magneto-optical trap (MOT) is about 9.0$\times 10^{6}$, which is an order of magnitude larger than the number of MgF molecules decelerated by the spontaneous radiation force. The results offer a promising starting point for further studies of sympathetic cooling.

Tunable magnomechanically and optomechanically induced transparency in a cavity opto-magnomechanical system

Ke Di(邸克), Huarong Xia(夏华容), Wenting Diao(刁文婷), Chunxiao Cai(蔡春晓), Wenhai Yang(杨文海), Yulian Qin(秦瑜莲), Ziting Liao(廖子婷), Yucan He(何钰灿), and Jiajia Du(杜佳佳)

Chin. Phys. B, 2025, 34 (7): 074201. DOI: 10.1088/1674-1056/adc18f

Abstract ( 172 )

HTML ( 0 )

PDF (889KB) ( 96 )

We demonstrate multiple transparency windows in a cavity opto-magnomechanical system containing a ferromagnetic material yttrium iron garnet (YIG) crystal. The probe output spectrum reveals the simultaneous emergence of three distinct phenomena: magnon-induced transparency (MIT) arising from microwave-magnon coupling; magnomechanically induced transparency (MMIT) through phonon-magnon interaction, and optomechanically induced transparency (OMIT) mediated by optical cavity-photon coupling. Crucially, these transparency features demonstrate dynamic tunability through precise manipulation of the number of interacting modes and coupling strengths. Our study reveals the effects of magnon-microwave and optomechanical coupling on probe results and the role of quantum interference mechanisms in a resonant system. Moreover, the fast-slow light effect can be enhanced and switched by choosing appropriate coupling parameters. Our work has potential applications in multi-band quantum storage and multi-channel photonic information processing devices.

Phase-modulated dynamical decoupling sequences robust to systematic amplitude error

Sijie Chen(陈思婕), Guanxing Chen(陈官幸), Jiahao Huang(黄嘉豪), Peiliang Liu(刘培亮), Min Zhuang(庄敏), and Chaohong Lee(李朝红)

Chin. Phys. B, 2025, 34 (7): 074202. DOI: 10.1088/1674-1056/adcd43

Abstract ( 154 )

HTML ( 0 )

PDF (1763KB) ( 5 )

Dynamical decoupling (DD), usually implemented by sophisticated sequences of instantaneous control pulses, is a well-established quantum control technique for quantum information and quantum sensing. In practice, the pulses are inevitably imperfect with many systematic errors that may influence the performances of DD. In particular, Rabi error and detuning are primary systemic errors arising from finite pulse duration, incorrect time control, and frequency instability. Here, we propose a phase-modulated DD with staggered global phases for the basic units of the pulse sequences to suppress these systemic errors. By varying the global phases appended to the pulses in the dynamical decoupling unit alternatively with 0 or $\pi$, our protocol can significantly reduce the influences of Rabi error and detuning. Our protocol is general and can be combined with the most existing DD sequences such as universal DD, knill DD, XY, etc. As an example, we further apply our method to quantum lock-in detection for measuring time-dependent alternating signals. Our study paves the way for a simple and feasible way to realize robust dynamical decoupling sequences, which can be applicable for various quantum sensing scenarios.

Optimization of wide frequency range 6H-SiC MEMS chips for a fiber optic Fabry-Perot accelerometer

Mariano Mahissi(马依思·马里亚诺), Xinli Ma(马新莉), Weiming Cai(蔡卫明), Xianmin Zhang(章献民), and Michel Dossou(多苏·米歇尔)

Chin. Phys. B, 2025, 34 (7): 074203. DOI: 10.1088/1674-1056/adc18e

Abstract ( 171 )

HTML ( 0 )

PDF (1077KB) ( 97 )

Vibration detection using sensors with both wide working frequency range, good sensitivity, and other good performances is a topic of great interest in fields such as inertial navigation, deep-sea fishing boat engines condition monitoring, seismic monitoring, attitude, and heading reference system, $etc$. This paper investigates two 6H-SIC MEMS diaphragms, one triangular and the other square, used in a fiber optic Fabry-Perot (FP) accelerometer in an experimental scenario. The triangular chip shows a wide working frequency range of 630 Hz-5300 Hz, a natural frequency of 44.3 kHz, and a mechanical sensitivity of 0.154 nm/g. An optimal structure of the square chip used in a probe such as a fiber optic FP accelerometer also shows a wide working frequency range of 120 Hz-2300 Hz; a good sensitivity of 31.5 mV/g, a resonance frequency of 7873 Hz, an accuracy of 0.96% F.S., a frequency measurement error of 1.15%, and an excellent linearity of 0.9995.

High-power ~ 4.1 μm quantum cascade lasers grown by metal-organic chemical vapor deposition

Chao Wang(王超), Chenhao Qian(钱晨灏), Yang Cheng(程洋), Junpu Wang(王俊普), Xiaoyue Luo(罗晓玥), Yuhang Zhang(章宇航), Wu Zhao(赵武), Fangyuan Sun(孙方圆), and Jun Wang(王俊)

Chin. Phys. B, 2025, 34 (7): 074204. DOI: 10.1088/1674-1056/adcdea

Abstract ( 172 )

HTML ( 0 )

PDF (1568KB) ( 98 )

The authors report the development of a $\lambda \sim 4.1$ μm quantum cascade laser grown by metal-organic chemical vapor deposition using strain-balanced InGaAs/InAlAs materials. A device with a 7.5 mm cavity length and 6.5 μm ridge width, bonded to an aluminum nitride heatsink, achieves maximum output powers of 3.4 W at 288 K in pulsed mode and 1.6 W at 288 K in continuous-wave (CW) operation, with corresponding maximum wall-plug efficiencies of 14.8% and 9.3%. A kink is observed in the power-current curve under CW operation, which is absent in pulsed operation. Near-field results show that in CW operation, the horizontal beam quality factor $M^{2}$ fluctuates with current, indicating mode instability and high-order lateral mode excitation, while in pulsed mode, the horizontal $M^{2}$ remains stable around 1.3 as the current increases from 1.4 A to 1.9 A.

Heterogeneous integration of silicon nitride photonics and CVD-grown WS₂ for second harmonic generation

Xuhang Jia(贾旭航), Bangren Xu(许邦仁), Jieyi Luo(罗劼舣), Ning Liu(刘宁), Yuhang Wang(王宇航), Biyuan Zheng(郑弼元), Wei Xu(徐威), and Ken Liu(刘肯)

Chin. Phys. B, 2025, 34 (7): 074205. DOI: 10.1088/1674-1056/adc7f7

Abstract ( 174 )

HTML ( 0 )

PDF (1241KB) ( 162 )

Silicon nitride photonics has emerged as a promising integrated optical platform due to its broad transparency window, low optical loss, and mature fabrication technology. However, the inherent centrosymmetric crystal structure of silicon nitride fundamentally restricts its applications in second-order nonlinear optical processes. Monolayer transition metal dichalcogenides, particularly tungsten disulfide (WS$_{2}$), exhibit strong second-order nonlinear responses, making them ideal candidates for nonlinear photonic applications. Herein, we demonstrate a heterogeneously integrated platform combining silicon nitride waveguides with chemical vapor deposition (CVD)-grown monolayer WS$_{2}$, enabling second harmonic generation. A specially designed silica cladding featuring gentle-slope profile on silicon nitride strip waveguides facilitates the integration of centimeter-scale WS$_{2}$ film with photonic circuits. This approach provides a robust solution for incorporating second-order nonlinearity into silicon nitride photonic systems. The demonstrated platform holds significant potential for advancing quantum networks, visible-light lasers, and integrated optical modulation/detection systems.

Real-time observations of the transition dynamics between multiple nonlinear states in a coherently driven Kerr fiber-loop resonator

Yayu Cao(曹亚昱), Heng Dong(董恒), and Xiankun Yao(姚献坤)

Chin. Phys. B, 2025, 34 (7): 074206. DOI: 10.1088/1674-1056/adc40a

Abstract ( 155 )

HTML ( 0 )

PDF (2548KB) ( 44 )

Passive Kerr fiber-loop resonators driven by coherent lasers exhibit a variety of nonlinear states, including modulation instability (MI), localized dissipative structures (solitons), and chaos. Although these transitions have been predicted theoretically, experimental real-time observations are rare in coherently driven Kerr fiber-loop resonators. In this study, we observed real-time transitions between the predicted nonlinear states by sweeping detuning both positively and negatively. We discovered the transition path between nonlinear states depending on the direction of detuning, providing new insights into the nonlinear dynamics. Our findings directly validate theoretical predictions and offer potential implications for future nonlinear optical applications.

Reconfigurable microring resonators for multipurpose quantum light sources

Yuxing Du(杜昱星), Yingwen Liu(刘英文), Chao Wu(吴超), Pingyu Zhu(朱枰谕), Chang Zhao(赵畅), Miaomiao Yu(余苗苗), Yan Wang(王焱), Kaikai Zhang(张凯凯), and Ping Xu(徐平)

Chin. Phys. B, 2025, 34 (7): 074207. DOI: 10.1088/1674-1056/adcc88

Abstract ( 149 )

HTML ( 0 )

PDF (5102KB) ( 125 )

Microring resonators (MRRs) are extensively utilized in photonic chips for generating quantum light sources and enabling high-efficiency nonlinear frequency conversion. However, conventional microrings are typically optimized for a single specific function, limiting their versatility in multifunctional applications. In this work, we propose a reconfigurable microring resonator architecture designed to accommodate diverse application requirements. By integrating a cascaded Mach-Zehnder interferometer (MZI) as the microring coupler, the design enables independent control of the quality factors for pump, signal and idler photons through two tunable phase shifters. This capability allows for dynamic tuning and optimization of critical performance parameters, including photon-pair generation rate (PGR), spectral purity and single photon heralding efficiency (HE). The proposed structure is implemented on a silicon photonic chip, and experimental results exhibit a wide range of tunability for these parameters, with excellent agreement with theoretical predictions. This flexible and multi-functional design offers a promising pathway for high-performance, highly integrated on-chip quantum information processing systems.

Giant-tunable bidirectional Goos-Hänchen shifts via phase change material-based metasurfaces with quasi-bound states in continuum

Jiaqing Liu(刘佳晴), Yue Zheng(郑悦), Xiao Li(李潇), Jingwen Li(李静文), Guohao Zhang(张国昊), Daxing Dong(董大兴), Dongmei Liu(刘冬梅), Yuwen Jia(贾玉雯), Yangyang Fu(伏洋洋), and Youwen Liu(刘友文)

Chin. Phys. B, 2025, 34 (7): 074208. DOI: 10.1088/1674-1056/adcdee

Abstract ( 180 )

HTML ( 0 )

PDF (1121KB) ( 76 )

We propose a novel approach for investigating the tunable Goos-Hänchen (GH) shift via an all-dielectric metasurface that incorporates phase change materials (PCMs). By introducing material asymmetry through the reconfigurable characteristic of PCMs while maintaining fixed geometric parameters, we can achieve tunable dual quasi-bound states in the continuum with ultrahigh quality factors (Q factors). Enabled by such tunable dual modes with significant phase changes, the PCM-based metasurface exhibits giant-tunable bidirectional GH shifts compared to conventional metasurfaces. Notably, the GH shift exhibits multidimensional tunability, including PCM-driven switching (amorphous to crystalline), incident-angle dependence (${\theta}$), and wavelength selectivity (${\lambda}$). The maximum observed shift reaches approximately 10$^{4}$ wavelengths, accompanied by a corresponding Q factor of 10$^{7}$. Our work demonstrates its potential for applications in ultrahigh-precision multifunctional devices, from biosensing to reconfigurable nanophotonic switches.

TaS₂-based saturable absorbers for Q-switched fiber laser applications

Qinghua Wang(汪情华), Hao Sun(孙昊), Chenhao Lu(鲁晨浩), Huiran Yang(杨慧苒), and Lu Li(李璐)

Chin. Phys. B, 2025, 34 (7): 074209. DOI: 10.1088/1674-1056/addcd7

Abstract ( 191 )

HTML ( 0 )

PDF (1703KB) ( 97 )

Transition metal disulfides are widely applied as nonlinear optical materials for laser pulse generation. In this paper, TaS$_{2}$ is successfully used for the first time to achieve a high-energy passively $Q$-switched erbium-doped fiber (EDF) laser. TaS$_{2}$ nanosheets are prepared by the liquid phase exfoliation method, and then the TaS$_{2}$ solution is mixed with polyvinyl alcohol (PVA). TaS$_{2}$/PVA film is prepared, which is cut into $\rm 1 mm \times 1 mm$ flakes. TaS$_{2}$/PVA saturable absorber (SA) is obtained by sandwiching a small flake between two fiber optic patch cable connectors. With the TaS$_{2}$/PVA SA added to an EDF laser, a $Q$-switched fiber laser with a center wavelength of 1560 nm and a repetition rate ranging from 51.33 kHz to 83.04 kHz is realized. At the pump power of 231 mW, the maximum output power is 1094 μW, and the shortest pulse duration is 3.48 μs. The results confirm that the TaS$_{2}$ material has excellent potential for application in nonlinear optics.

Pulsed single-longitudinal-mode operation based on modal-gain difference in repetitively passively Q-switched lasers

Jinhe Yuan(袁晋鹤), Mofan Yang(杨莫凡), and Ziyi Wu(武子怡)

Chin. Phys. B, 2025, 34 (7): 074210. DOI: 10.1088/1674-1056/adc665

Abstract ( 124 )

HTML ( 0 )

PDF (822KB) ( 39 )

The pulsed single-longitudinal-mode (SLM) operation caused by the modal-gain difference in a repetitively passively $Q$-switched (PQS) laser is studied in detail. Firstly, the analytical expressions for the pulse buildup-time difference of repetitively PQS four-level and quasi-three-level lasers have been developed respectively. Then, according to the temporal criterion, the required conditions for repetitively PQS four-level and quasi-three-level lasers to achieve SLM operation are analyzed. The analysis results show that in addition to the short cavity is conducive to obtaining the pulsed SLM laser, the use of a lower pump power (compared to the threshold power) will help to obtain a longer pulse buildup-time difference and thus enabling the SLM operation. Moreover, it is worth noting that for the quasi-three-level lasers, the pulse buildup-time difference also depends on the initial population inversion density. The results also reveal that setting resonator parameters that can obtain large initial population inversion density will be helpful to the SLM operation in both four-level and quasi-three-level regimes. In addition, the use of saturable absorber with a low absorption cross-section ratio between the excited state and ground state also contributes to the realization of the SLM. Finally, the optimization model of passively $Q$-switched single-longitudinal-mode laser is established. In addition to predicting the output performance of the laser, this model can also be used to obtain the optimal resonator parameters and the upper limit of pump power for SLM operation.

Effective working regions of the grating chip for planar-integrated magneto-optics trap

Chang-Jiang Huang(黄长江), Ling-Xiao Wang(王凌潇), Liang Chen(陈梁), Chuan-Feng Li(李传锋), Guang-Can Guo(郭光灿), Chang-Ling Zou(邹长铃), and Guo-Yong Xiang(项国勇)

Chin. Phys. B, 2025, 34 (7): 074211. DOI: 10.1088/1674-1056/adcb9c

Abstract ( 206 )

HTML ( 1 )

PDF (1550KB) ( 75 )

We experimentally investigate the effective working regions of a planar-integrated magneto-optical trap (MOT). By scanning a blocking point in the incident laser beam, we identify four effective working regions of the laser beam contributing to MOT: a central region corresponding to the downward incident beam and three regions associated with the upward diffracted beams. The latter three regions are the effective regions of the grating chip. It is demonstrated that only three 3.5 mm radius grating regions can produce a MOT that is capable of trapping $10^5$ atoms with a temperature below 150 μK, retaining over 60% of atoms compared to a complete grating chip. This finding suggests that more than 60% of the grating chip area can be saved for other on-chip components, such as metasurfaces and nanophotonic devices, without significantly compromising MOT performance, paving the way for more compact and versatile atom-photon interfaces.

Temperature and acoustic impedance simultaneous sensor based on forward stimulated Brillouin scattering in highly nonlinear fiber

Shilong Liu(刘仕龙), Yang Li(李阳), Hongbin Hu(胡洪彬), Bing Sun(孙兵), and Zuxing Zhang(张祖兴)

Chin. Phys. B, 2025, 34 (7): 074212. DOI: 10.1088/1674-1056/adca1b

Abstract ( 192 )

HTML ( 0 )

PDF (6222KB) ( 48 )

A temperature and acoustic impedance simultaneous sensor based on forward stimulated Brillouin scattering (FSBS) in highly nonlinear fiber (HNLF) with high sensitivity and high accuracy is proposed and demonstrated in this paper. High-order acoustic modes (HOAMs) are used to achieve individual or simultaneous measurement of the two parameters. Transverse acoustic waves (TAWs) involved in the FSBS process can efficiently sense the mechanical or environmental changes outside the fiber cladding, which will be reflected in a linear shift of the acoustic resonance frequency. By analyzing the frequencies of specific scattering peaks, the temperature and acoustic impedance outside the fiber cladding can be obtained simultaneously. The highest measured temperature and acoustic impedance sensitivities are 184.93 kHz/$^\circ$C and 444.56 kHz/MRayl, and the measurement accuracies are 0.09 $^\circ$C and 0.009 MRayl, respectively, which are both at desirable levels. We believe this work can provide potential application solutions for sensing fields involving temperature or acoustic impedance measurements.

All-chalcogenide glass based high fill-factor long-wave infrared micro-metalens array with superior optical flexibility

Zhaofeng Gu(谷招峰), Kongsi Zhou(周孔思), Tong Sun(孙童), Yixiao Gao(高一骁), Yimin Chen(陈益敏), Zijun Liu(刘自军), Chenjie Gu(顾辰杰), Pengfei Lu(芦鹏飞), and Xiang Shen(沈祥)

Chin. Phys. B, 2025, 34 (7): 074213. DOI: 10.1088/1674-1056/add4f5

Abstract ( 130 )

HTML ( 0 )

PDF (4457KB) ( 123 )

Long-wave infrared (LWIR) micro-metalens arrays have emerged as highly flexible and multifunctional optical elements, significantly enhancing the performance of infrared imaging systems. In this work, two types of chalcogenide glass based LWIR micro-metalens arrays with $10 \times 10$ array-size and 100% fill factor were designed and investigated. Specifically, the first one possesses a uniform focal length of 110 μm, and it can efficiently focus the incident light (9.78 μm) into a spot with a full width at half maximum (FWHM) of approximately 11.5 μm ($\sim 1.18\lambda $). Additionally, the second one features flexible and configurable focal lengths of the respective micro-metalenses in the array, and focal lengths of 102 μm, 149 μm, and 182 μm can be achieved on one substrate, while it still retains the same optical performance as the micro-metalens array with a single focal length. Overall, these all-chalcogenide glass based LWIR micro-metasurface arrays possess significant potential for integrating within advanced infrared imaging systems in the future.

Spectral photon-number distribution of parametric down-conversion and generation of heralded Fock states

Yan-Sheng Bao(包燕升), Bo-Chen Wang(王搏尘), Chang-Yong Tian(田昌勇), and Zheng-Yong Li(李政勇)

Chin. Phys. B, 2025, 34 (7): 074214. DOI: 10.1088/1674-1056/add904

Abstract ( 165 )

HTML ( 0 )

PDF (4988KB) ( 53 )

Photon pairs with large nondegeneracy have recently attracted increasing interest, which gives rise to an urgent demand for revealing their complete and accurate spectral distribution. By thoroughly analyzing parametric down-conversion (PDC), we put forward a model to directly describe the spatial-spectral distribution of these photon pairs, which is experimentally demonstrated by a 532-nm pumped type-I PDC in a beta barium borate (BBO) crystal. The measured spectral curves show good agreement with the theoretical predictions over the entire spectral range. We further demonstrate that, as signal wavelength increases, the photon pairs are initially spectrally distinguishable, then partly indistinguishable, finally completely indistinguishable with a maximum bandwidth of approximately 500 nm. Utilizing photon-number-resolving single-photon detectors (SPD), we observe the average photon number decreases significantly more slowly than the spectral intensity as the wavelength deviates from the peak, and the photon numbers follow a quasi-Poisson distribution well for wavelengths around the peak, but a thermal distribution better describes the statistics near the spectral boundaries. Finally, we use the signal photons as the trigger to generate heralded Fock states up to 10 photons in near-infrared range, which are suitable for quantum simulation and quantum key distribution in optical fiber networks.

Self-organized phase-locking of a mixed-resonant cavity diode laser array enabled by on-chip Talbot effect

Jun Qi(齐军), Tian Lan(兰天), Jing-Hao Zhang(张敬昊), Ying Li(李颖), Yi-Wen Lou(楼亦文), Feng-Jiao Qin(覃凤姣), Yu-Ying Liu(刘豫颖), and Zhi-Yong Wang(王智勇)

Chin. Phys. B, 2025, 34 (7): 074215. DOI: 10.1088/1674-1056/ade387

Abstract ( 163 )

HTML ( 0 )

PDF (3188KB) ( 77 )

To address the challenge of achieving stable in-phase coherent optical field in high-power laser arrays, we propose a novel dual Talbot diffraction coupling method that combines the on-chip self-injection effect with a mixed-resonant cavity diode laser array (MDLA). The designed MDLA incorporates two types of resonant cavities and an integrated external fractional Talbot cavity to compensate for in-phase mode phase delays. Numerical simulations demonstrate that the near-field optical pattern can be self-imaged via self-organized phase-locking, while the far-field optical pattern of in-phase mode can be coherently enhanced and modulated to exhibit a single-lobe pattern successfully. Furthermore, this method could inherently provide strong optical coupling and overcome the limited scalability of the weakly-coupled laser arrays. Ultimately, by leveraging self-organized phase-locking and Talbot-induced mode discrimination, our approach offers a robust platform for realizing high-power coherent laser sources with scalable integration potential.

Performance of tubular actuators constructed with dielectric elastomer materials

Chengguang Zhang(张成光)

Chin. Phys. B, 2025, 34 (7): 074501. DOI: 10.1088/1674-1056/add007

Abstract ( 156 )

HTML ( 1 )

PDF (842KB) ( 38 )

Soft underwater swimming robots driven by smart materials show unique advantages in ocean exploration, such as low noise, high flexibility and good environmental interaction ability. The dielectric elastomer (DE), as a new kind of soft intelligent material, has the characteristics of a low elastic modulus, large deformation range, high energy density and fast response speed. DE actuator (DEA) drive systems use the deformation characteristics of dielectric materials to drive the mechanical system, which has become a research hotspot in the field of soft robots. In this paper, a tubular actuator based on DEs is designed and its performance is studied. Firstly, the structure and driving process of a DEA are described, and a tubular DEA is designed. Studying the elongation ratio of the DEA pre-stretching shows that when the axial elongation ratio is 3 times and the circumferential elongation ratio is 4 times, the maximum deformation effect can be obtained under voltage excitation. At a voltage of 6.0 kV, a single pipe section DEA achieves a bending angle of 25.9$^\circ$ and a driving force of 73.8 mN. Secondly, the effect of the DEA series on the bending angle and response characteristics is studied. The experimental results show that the maximum bending angle of the three joint actuators in series can reach 59.3$^\circ$ under 6.0 kV voltage, which significantly improves the overall bending performance. In addition, the truncation frequency of the drive module after the series is increased to 0.62 Hz, showing better frequency response capability. The excellent performance of the pipe joint actuator in its bending angle, response characteristic and driving force is verified.

Diagnosis of electron temperature of copper foil plasmas produced at the Shenguang-II facility

Chenglong Zhang(张成龙), Haochen Gu(谷昊琛), Yu Dai(戴羽), Ke Fang(方可), Yufeng Dong(董玉峰), Peng Zhou(周鹏), and Yingjun Li(李英骏)

Chin. Phys. B, 2025, 34 (7): 075202. DOI: 10.1088/1674-1056/adca19

Abstract ( 90 )

HTML ( 0 )

PDF (1669KB) ( 60 )

Warm dense plasmas are crucial for high-energy-density physics and inertial confinement fusion research. Experiments involving laser-irradiated copper (Cu) foil were performed at the Shenguang-II facility. A highly oriented pyrolytic graphite crystal spectrometer measured the time-integrated spectral distribution of Cu under varying laser intensities. Using the two-dimensional radiation-hydrodynamics code FLASH and the spectral analysis code FLYCHK, we simulated the temporal evolution of plasma density and temperature distributions, as well as the emission intensities of spectral lines at different temperatures and densities. The simulation results revealed that the two-electron satellite lines ($J$) and the resonance line ($W$) emissions of Cu originate predominantly from the radiation region near the critical density surface, with a density range from approximately 0.5$ n_{\rm c}$ to 1.0$ n_{\rm c}$, and radiate primarily during the laser irradiation period. By analyzing the $J/W$ intensity ratio of the measured spectral lines, we estimated the electron temperatures near the critical-density surface under different laser intensities.

A kinetic simulation study of glow discharges within millimeter-scale hollow anode

Yaoyu Ren(任耀宇) and Chaohui Lan(蓝朝晖)

Chin. Phys. B, 2025, 34 (7): 075203. DOI: 10.1088/1674-1056/adca15

Abstract ( 101 )

HTML ( 0 )

PDF (1156KB) ( 25 )

This paper presents a numerical simulation of DC glow discharge at 2 Torr (1 Torr = 1.33322$\times10^2$ Pa) with a microhollow anode, using a two-dimensional (2D) PIC/MCC code to explore the impact of the hollow anode structure on discharge characteristics. Simulation results show that the plasma density in the anode channel decreases exponentially along the $x$-direction towards the outlet while the electric potential decreases linearly. The electron temperature, derived from the relationship between density and electric potential, shows a good agreement with the calculated temperature. The potential peak at the inlet, along with the grounded anode, forms a transverse potential well that draws electrons toward the center of the channel. The $x$-direction electric field, generated by the potential difference between the inlet and outlet of the anode, directs electrons toward the inlet of the anode. Low-energy electrons are confined within the potential well, while very few high-energy electrons outlet the channel. The hollow anode structure serves as a collimator for electrons, leading to an increment of moderate-velocity electron flux in the anode channel. Shortening the anode leads to a slower rate of density decrease, resulting in a higher density at the outlet.

Performance enhancement of IGZO thin-film transistors via ultra-thin HfO₂ and the implementation of logic device functionality

Xuyang Li(栗旭阳), Bin Liu(刘斌), Xianwen Liu(刘贤文), Shuo Zhang(张硕), Congyang Wen(温丛阳), Jin Zhang(张进), Haifeng Liang(梁海锋), Guangcai Yuan(袁广才), Jianshe Xue(薛建设), and Zhinong Yu(喻志农)

Chin. Phys. B, 2025, 34 (7): 076101. DOI: 10.1088/1674-1056/adcb22

Abstract ( 160 )

HTML ( 2 )

PDF (1353KB) ( 657 )

The enhancement of mobility has always been a research focus in the field of thin-film transistors (TFTs). In this paper, we report a method using ultra-thin HfO$_{2}$ to improve the electrical performance of indium gallium zinc oxide (IGZO) TFTs. HfO$_{2}$ not only repairs the surface morphology of the active layer, but also increases the carrier concentration. When the thickness of the HfO$_{2}$ film was 3 nm, the mobility of the device was doubled (14.9 cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1} \to 29.6 $ cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1}$), and the device exhibited excellent logic device performance. This paper provides a simple and effective method to enhance the electrical performance of IGZO TFTs, offering new ideas and experimental foundation for research into high-performance metal oxide (MO) TFTs.

Aligning and flocking of ellipsoidal Quincke rollers by flipping

Kai-Xuan He(何凯旋), Qi-Ying Ni(倪琦英), Xiao-Yi Zhou(周晓怡), Wen-De Tian(田文得), Kang Chen(陈康), and Tian-Hui Zhang(张天辉)

Chin. Phys. B, 2025, 34 (7): 076401. DOI: 10.1088/1674-1056/adc669

Abstract ( 158 )

HTML ( 0 )

PDF (3074KB) ( 28 )

Active rods propelled along their long axis align their velocities and orientations simultaneously in collision. However, as the propulsion is perpendicular to the long axis, velocity alignment becomes dynamically difficult. Here, we show that ellipsoidal Quincke roller propelled along their short-axis (perpendicular to the long axis) can align their velocities by flipping and form flocking with nematic order. The flipping arises from the reversible transition between the static parallel spinless state and the spinning transversal state of ellipsoidal Quincke rollers. This is possible only near (above) the critical field where both the parallel spinless state and the spinning transversal spinning are metastable. The flipping-facilitated alignment offers an extra aligning mechanism for elongate active agents, and the resulting active liquid crystals serve a model system to explore the defect dynamics as the propulsion deviates from the local nematic orientation which has not been addressed yet.

Molecular-dynamics simulations on the crystallization of Fe metallic glasses under alternating magnetic field

Yanxue Wu(吴言雪), Qiang-Qiang Pan(潘强强), Rui Ning(宁睿), and Hailong Peng(彭海龙)

Chin. Phys. B, 2025, 34 (7): 076402. DOI: 10.1088/1674-1056/adcb25

Abstract ( 112 )

HTML ( 0 )

PDF (1643KB) ( 13 )

We performed the coupled molecular-dynamics and spin dynamics simulations to investigate the magnetic annealing effect on the crystallization behavior of Fe metallic glasses (MGs). By calculating the local five-fold symmetry, Voronoi polyhedron, and bond orientational order parameters, we find a significant structural evolution at high-frequency magnetic annealing: the icosahedral order diminishes, and the crystalline-like order is enhanced, comparing to the case without magnetic field. The fraction of the body-centered cubic structures remarkably increases with the frequency of magnetic annealing, and the atoms of these order show a tendency of aggregating in space to form the crystalline nuclei. These findings unveil how the local structure evolves under magnetic annealing, and the accelerated crystallization process of MGs through alternating magnetic fields.

Structural and transport properties of a-RbCu₄Cl₃I₂ at room temperature by molecular dynamics simulation

Yueqiang Lan(兰越强), Tushagu Abudouwufu(吐沙姑·阿不都吾甫), Alexander Tolstoguzov, and Dejun Fu(付德君)

Chin. Phys. B, 2025, 34 (7): 076501. DOI: 10.1088/1674-1056/adc18d

Abstract ( 106 )

HTML ( 0 )

PDF (900KB) ( 26 )

Considering $\alpha $-RbCu$_{4}$Cl$_{3}$I$_{2}$ is isostructural with $\alpha $-RbAg$_{4}$I$_{5}$, in this work, we built a molecular dynamics simulation system of the former superionic conductor with an empirical pairwise potential model, which was verified on the latter crystal, including long-ranging Coulomb, short-ranging Born-Mayer, charge-dipole, and dipole-quadrupole interactions. The corresponding parameters were collected from the crystal structure and several reports of interionic potentials in alkali halides. The coordination number of fixed ions was examined, and the dynamic distribution of dissociative Cu$^{+}$ was described by the radial distribution function. The diffusion behavior of the ions was evaluated with mean square displacements and velocity auto-correlation functions. The diffusion coefficient of copper ions obtained is ($47.9\pm 6.1$)$\times10^{-7}$ cm$^{2}$/s, which is approximately 37 times that of the simulation result ($1.3\pm 0.1$)$\times10^{-7}$ cm$^{2}$/s of silver in $\alpha $-RbAg$_{4}$I$_{5}$ at room temperature. In this work, the diffusion coefficient of Cu$^{+}$ was first discussed by molecule simulation, while there are few experimental reports.

Three-dimensional ResNet for efficient prediction of ground state phases in multicomponent dipolar spinor BECs

Chengji Liao(廖承继), Tiantian Li(李甜甜), Xiao-Dong Bai(柏小东), and Yunbo Zhang(张云波)

Chin. Phys. B, 2025, 34 (7): 076701. DOI: 10.1088/1674-1056/adc7f9

Abstract ( 118 )

HTML ( 1 )

PDF (1093KB) ( 42 )

Machine learning has rapidly become a powerful tool for addressing challenges in ultracold atomic systems; however, its application to intricate three-dimensional (3D) systems remains relatively underexplored. In this study, we introduce a 3D residual network (3D ResNet) framework based on 3D convolutional neural networks (3D CNN) to predict ground states phases in 3D dipolar spinor Bose-Einstein condensates (BECs). Our results show that the 3D ResNet framework predicts ground states with high accuracy and efficiency across a broad parameter space. To enhance phase transition predictions, we incorporate data augmentation techniques, leading to a notable improvement in the model's performance. The method is further validated in more complex scenarios, particularly when transverse magnetic fields are introduced. Compared to conventional imaginary-time evolution methods (ITEM), the 3D ResNet drastically reduces computational costs, offering a rapid and scalable solution for complex 3D multi-parameter nonlinear systems.

Competing phases and suppression of superconductivity in hole-doped Hubbard model on honeycomb lattice

Hao Zhang(张浩), Shaojun Dong(董少钧), and Lixin He(何力新)

Chin. Phys. B, 2025, 34 (7): 077102. DOI: 10.1088/1674-1056/adcb20

Abstract ( 121 )

HTML ( 0 )

PDF (683KB) ( 87 )

We investigate the hole-doped Hubbard model on a honeycomb lattice using a fermionic projected entangled pair states (fPEPS) method. Our study reveals the presence of quasi-long-range order of Cooper pairs, characterized by power-law decay of correlation functions with exponents $K>1$. We further analyze the competing phases of superconductivity, specifically the antiferromagnetic (AFM) order and the charge density wave (CDW) order. Our results show that there are domain wall structures when the hole doping $\delta$ is small and the Coulomb parameter $U$ is large. However, these structures disappear as we increase the hole doping $\delta$ or decrease $U$. Furthermore, for small hole doping, the system exhibits AFM order, which diminishes for $\delta > 0.05$. Conversely, as the doping level increases, the CDW order gradually decreases. Notably, a considerable CDW order persists even at higher doping levels. These findings suggest a progressive suppression of the AFM order and a growing prominence of the CDW order with increasing $\delta$.

Anomalous ultrafast thermalization of photoexcited carriers in two-dimensional materials induced by orbital coupling

Zhuoqun Wen(文卓群), Haiyu Zhu(诸海渝), Wen-Hao Liu(刘文浩), Zhi Wang(王峙), Wen Xiong(熊稳), and Xingzhan Wei(魏兴战)

Chin. Phys. B, 2025, 34 (7): 077103. DOI: 10.1088/1674-1056/adc191

Abstract ( 108 )

HTML ( 0 )

PDF (1201KB) ( 34 )

Understanding the dynamics of photoexcited carriers is essential for advancing photoelectronic device design. Photon absorption generates electron-hole pairs, and subsequent scatterings can induce ultrafast thermalization within a picosecond, forming a quasi-equilibrium distribution with overheated electrons. The high-energy tail of this distribution enables carriers to overcome energy barriers, thereby enhancing quantum efficiency - a phenomenon known as photothermionic emission (PTE). Despite its importance, the onset and mechanisms of PTE remain under debate. Using real-time time-dependent density functional theory (rt-TDDFT), we investigate ultrafast carrier thermalization in two-dimensional (2D) materials graphene and PtTe$_{2}$, and the results reveal distinct differences. In graphene, both electrons and holes thermalize into Fermi-Dirac distributions with good agreement to experiment, while PtTe$_{2}$ exhibits anomalous high-energy tails for both electrons and holes, deviating significantly from Fermi-Dirac behavior. We attribute this anomaly to differences in orbital coupling between the two materials, from which we derive design principles for identifying optimal PTE candidates and, ultimately, improving photodetector performance.

Non-Hermitian birefringent Dirac fermions driven by electromagnetic fields

Kai Liu(刘恺), Wan-Zi Sun(孙万梓), Cheng-Xi Li(李成蹊), and Wu-Ming Liu(刘伍明)

Chin. Phys. B, 2025, 34 (7): 077104. DOI: 10.1088/1674-1056/adcaa1

Abstract ( 115 )

HTML ( 0 )

PDF (2297KB) ( 16 )

We investigate the behavior of non-Hermitian birefringent Dirac fermions by examining their interaction with electromagnetic fields through renormalization group analysis. Our research reveals that the interplay between non-Hermiticity and birefringence leads to distinct behaviors in two and three dimensions, where the system exhibits different fixed points and scaling properties due to dimension-dependent charge renormalization effects. In two dimensions, where the electronic charge remains unrenormalized, the system flows in the deep infrared limit from non-Hermitian birefringent spin-3/2 fermions to two copies of non-Hermitian spin-1/2 Dirac fermions, demonstrating a crossover of relativistic liquid and non-relativistic liquid. In three dimensions, dynamic screening of electromagnetic interactions modifies the logarithmic growth of Fermi velocity, leading to richer quantum corrections while maintaining similar suppression of birefringence in the infrared limit. Our findings provide theoretical insights into the emergence of Lorentz symmetry in non-Hermitian systems, laying theoretical foundations for studying low-energy behavior in other non-Hermitian models.

Impact of epitaxial structural parameters on two-dimensional hole gas properties in p-GaN/AlGaN/GaN heterostructures

Fuzhou Wen(文福洲), Qianshu Wu(吴千树), Jinwei Zhang(张津玮), Zhuoran Luo(罗卓然), Senyuan Xu(许森源), Hao Jiang(江灏), and Yang Liu(刘扬)

Chin. Phys. B, 2025, 34 (7): 077105. DOI: 10.1088/1674-1056/adc97e

Abstract ( 146 )

HTML ( 0 )

PDF (1286KB) ( 71 )

Research on p-channel field-effect transistors (p-FETs) remains limited, primarily due to the significantly lower conductivity of the two-dimensional hole gas (2DHG) compared to the two-dimensional electron gas (2DEG) in n-channel field-effect transistors (n-FETs), which poses a significant challenge for monolithic integration. In this study, we investigate the impact of epitaxial structure parameters on 2DHG properties in p-GaN/AlGaN/GaN heterostructures through semiconductor technology computer-aided design (TCAD) simulations and theoretical calculations, identifying the conditions necessary to achieve high-density 2DHG. Our simulations demonstrate that increasing the p-GaN thickness leads to two critical thicknesses determined by surface states and acceptor ionization concentration: one corresponds to the onset of 2DHG formation, and the other to its saturation. Lowering the donor surface state energy level and increasing the acceptor ionization concentration promote 2DHG formation and saturation, although the saturated density remains independent of surface states. Additionally, a higher Al composition enhances intrinsic ionization due to stronger polarization effects, thereby increasing the 2DHG sheet density. Consequently, to achieve high-density 2DHG in p-GaN/AlGaN/GaN heterostructures, it is essential to increase the Al composition, ensure that the p-GaN thickness exceeds the critical thickness for 2DHG saturation, and maximize the acceptor ionization concentration. This study elucidates the impact of epitaxial structure parameters on 2DHG properties in p-GaN/AlGaN/GaN heterostructures and provides valuable guidance for the optimization of p-FET designs.

CMOS compatibility and excellent resistive switching of tantalum oxide-based resistive switching memory

Liping Fu(傅丽萍), Gaoyuan Pan(潘高远), Rui Hao(郝瑞), Xiaolong Fan(范小龙), and Yingtao Li(李颖弢)

Chin. Phys. B, 2025, 34 (7): 077201. DOI: 10.1088/1674-1056/adcc86

Abstract ( 130 )

HTML ( 0 )

PDF (1774KB) ( 103 )

A CMOS compatible RRAM device with TaN/Ta/TaO$_{x}$/TaN structure was proposed for nonvolatile memory applications. Excellent resistive switching characteristics, including low operation voltages ($< 1$ V), low operation current (< 100 μA), good programming/erasing endurance ($> 10^{6}$ cycles), satisfactory uniformity, and reliable data retention, have been demonstrated. Furthermore, all of the elements in the fabricated TaN/Ta/TaO$_{x}$/TaN devices are highly compatible with modern CMOS manufacturing process, showing promising application in the next generation of nonvolatile memory.

Current density in anomalous Hall effect regime under weak scattering

Ning Dai(戴凝) and Bin Zhou(周斌)

Chin. Phys. B, 2025, 34 (7): 077301. DOI: 10.1088/1674-1056/adcd42

Abstract ( 149 )

HTML ( 0 )

PDF (1863KB) ( 45 )

A finite equilibrium current density arises in the anomalous Hall effect (AHE) as a result of time-reversal symmetry breaking, affecting both the differential current density and total current. In this paper, we illustrate the equilibrium current density in a ribbon-shaped system within the AHE regime, consisting of two sets of counterpropagating channels arranged in a zebra stripes pattern. While the middle channels are susceptible to scattering, the edge channels remain relatively robust. Despite this difference, all channels exhibit the same differential current density when subjected to a differential voltage across the two ends of the ribbon. When a differential voltage is applied to both sides of the ribbon, it results in a snaking pattern of differential current density forming across it. Furthermore, in a four-terminal device comprising the ribbon and two normal leads, it is found that Hall conductance is independent of ribbon width within certain scattering strengths due to the differences in robustness between middle and edge channels. These findings disclose the details of the AHE transport in a finite-sized system under weak scattering.

Role of symmetry in antiferromagnetic topological insulators

Sahar Ghasemi and Morad Ebrahimkhas

Chin. Phys. B, 2025, 34 (7): 077302. DOI: 10.1088/1674-1056/adcb1e

Abstract ( 96 )

HTML ( 0 )

PDF (647KB) ( 40 )

In this investigation, we delve into the interplay between strong interactions and intricate topological configurations, leading to emergent quantum states such as magnetic topological insulators. The crux of our research centers on elucidating how lattice symmetry modulates antiferromagnetic quantum Hall phenomena. Utilizing the spinful Harper-Hofstadter model enriched with a next-nearest-neighbor (NNN) hopping term, we discern a half-filling bandgap, paving the way for the manifestation of a quantum Hall insulator characterized by a Chern number, $C = 2$. Upon integrating a checkerboard-patterned staggered potential ($\varDelta $) and the Hubbard interaction ($U$), the system exhibits complex dynamical behaviors. Marginal NNN hopping culminates in a Neél antiferromagnetic Mott insulator. In contrast, intensified hopping results in stripe antiferromagnetic configurations. Moreover, in the regime of limited NNN hopping, a $C = 1$ Neél antiferromagnetic quantum Hall insulator emerges. A salient observation pertains to the manifestation of a $C = 1$ antiferromagnetic quantum Hall insulator when spin-flip mechanisms are not offset by space group symmetries. These findings chart a pathway for further explorations into antiferromagnetic Quantum Hall States.

Influence of sputtering ambient with hydrogen gas on optoelectrical properties of Ta-doped tin oxide

Haozhen Li(李昊臻), Xingqian Chen(陈兴谦), Minqiu Du(杜敏求), Wei Chen(陈伟), and Xiaolong Du(杜小龙)

Chin. Phys. B, 2025, 34 (7): 077303. DOI: 10.1088/1674-1056/adc97f

Abstract ( 115 )

HTML ( 0 )

PDF (3331KB) ( 193 )

Ta-doped SnO$_{2}$ (TTO) is a suitable candidate to replace transparent conductive oxide (TCO) composed of expensive indium used for optoelectronics and silicon heterojunction solar cells fabricated below 200 ${^\circ}$C. However, TTO films fabricated by sputtering at low temperature still demonstrate too high resistance and optical absorptance for application in industry. In this study, we investigate the influence of sputtering ambient on the optoelectrical properties of TTO films. The addition of hydrogen and oxygen to argon during sputtering leads to a large improvement in the optoelectrical properties of TTO films. The best TTO film has a low average absorptance of 1.9% and a low resistance of $3.8\times 10^{-3}$ $\Omega \cdot$cm with a high carrier density of $9.3\times 10^{19}$ cm$^{-3}$ and mobility of 17.8 cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1}$. The microstructural and compositional properties of TTO films were characterized using x-ray diffraction, x-ray photoelectron spectroscopy and UV-Vis spectrophotometry. A proper ratio of hydrogen to oxygen in the sputtering gas improves the crystallinity and the doping efficiency of Ta. Optical absorptance is also reduced with suppressed formation of Sn(II) in the TTO films. Therefore, our findings exhibit remarkable potential for the industrial application of TTO as a low-cost TCO.

Ultrafast electron transport in 2D van der Waals heterostructures Bi₂Te₃/Fe₄GeTe₂ probed by terahertz spectroscopy

Hui-Xiang Hong(洪晖祥), Yun Sun(孙芸), Jing Li(李竞), Jing-Yi Peng(彭静宜), Hui-Ping Zhang(张慧萍), Hong-Guang Li(李宏光), Shao-Hui Wu(吴少晖), Tian-Xiao Nie(聂天晓), Yan Peng(彭滟), and Zuan-Ming Jin(金钻明)

Chin. Phys. B, 2025, 34 (7): 077304. DOI: 10.1088/1674-1056/adcdf2

Abstract ( 117 )

HTML ( 0 )

PDF (5675KB) ( 58 )

The research on two-dimensional (2D) magnetic materials and their heterostructures is crucial in fields like spintronics, materials science, and condensed matter physics. This study uses terahertz (THz) time-domain spectroscopy to investigate ultrafast electron transport properties in both van der Waals Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ ferromagnetic/topological heterostructures. Our results show that these heterostructures exhibit effective THz electromagnetic shielding. The complex conductivity spectra of Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ heterostructures with varying Fe$_{4}$GeTe$_{2}$ thicknesses are analyzed using the Drude-Smith model. We quantitatively examine how Fe$_{4}$GeTe$_{2}$ layer thickness affects the direct current conductivity, plasma frequency, carrier momentum scattering time, and back-scattering coefficient. As the number of Fe$_{4}$GeTe$_{2}$ layers increases, intra-layer back-scattering events for charge carriers become more frequent. This work provides THz frequency spectra for both Fe$_{4}$GeTe$_{2}$ and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$, aiding in the design and optimization of THz modulators and detectors.

Fabrication and characterization of MgB₂ spherical shells with reduced thickness on 1 mm diameter Si₃N₄ spheres

Ruining Sun(孙瑞宁), Tiequan Xu(徐铁权), Yue Wang(王越), Furen Wang(王福仁), and Zizhao Gan(甘子钊)

Chin. Phys. B, 2025, 34 (7): 077402. DOI: 10.1088/1674-1056/adcdec

Abstract ( 148 )

HTML ( 0 )

PDF (1554KB) ( 75 )

Magnetic levitation of the fusion target by coating a thin MgB$_2$ superconducting shell on its outer surface has recently been proposed in inertial confinement fusion (ICF) to realize a noncontact support of the target at $\sim20$ K to boost the implosion performance and fusion yield. To avoid possible effects on target ablation, the coated MgB$_2$ shell is anticipated to be as thin as possible while fulfilling the target levitation requirements. Under this circumstance, the fabrication of an MgB$_2$ shell with reduced thickness has been explored using a hybrid physical-chemical vapour deposition method. By gradually decreasing the deposition time, a set of MgB$_2$ shells were grown on 1 mm diameter Si$_3$N$_4$ spheres with the thickness reducing from 720 nm to 200 nm. The spherical shells all have a polycrystalline structure characterized by closely packed hexagonal grains, with both the grain size and thickness diminishing as the shell thickness decreases. The superconducting transition temperature $T_{\rm c}$ of the shells, as determined by both resistance and magnetization measurements, is in the range of $38$-$40$ K and all shells exhibit ideal diamagnetism at low temperatures. For the thinnest shell of 200 nm, the superconducting critical current density $J_{\rm c}$ at 20 K reaches $8.0\times10^6$ A/cm$^2$ and $2.1\times10^5$ A/cm$^2$ under zero and 2 T applied field, respectively. The results indicate that it is experimentally feasible to fabricate MgB$_2$ spherical shells with a thickness as low as 200 nm while maintaining the high $T_{\rm c}$ and $J_{\rm c}$, thereby taking a further step towards the application of the shell in superconducting magnetic levitation for ICF.

One-step synthesis of ThMn₁₂-type Sm_0.8Zr_0.2Fe₁₁SiB_x (x =0-0.2) ribbon magnets via rapid solidification

Chi Zhang(张驰), Hui-Dong Qian(千辉东), Wenyun Yang(杨文云), Jingzhi Han(韩景智), Xuegang Chen(陈学刚), and Jinbo Yang(杨金波)

Chin. Phys. B, 2025, 34 (7): 077501. DOI: 10.1088/1674-1056/add006

Abstract ( 109 )

HTML ( 0 )

PDF (1460KB) ( 33 )

ThMn$_{12}$-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties. However, challenges such as the metastable nature of the ThMn$_{12}$-type phase, excessively small single-domain grain size, and complex fabrication processes have hindered the achievement of high phase purity, uniform microstructure, and desirable extrinsic performance. In this study, we directly synthesized ThMn$_{12}$-type Sm$_{0.8}$Zr$_{0.2}$Fe$_{11}$SiB$_{x}$ ($x = 0$-0.2) ribbon magnets via boron doping combined with a one-step rapid solidification method. This approach not only simplifies the fabrication process but also enhances phase stability and achieves a uniform microstructure with high ThMn$_{12}$-type phase purity. By optimizing the boron content and cooling rate, the resulting magnets exhibit a coercivity ($H_{\rm c}$) of 6222 Oe, a remanence ($M_{\rm r}$) of 80 emu/g, and a remanence ratio ($M_{\rm r}/M_{\rm s}$) of 0.71. This work demonstrates a streamlined approach to producing high-performance ThMn$_{12}$-type magnets and provides insights into their practical application potential.

Deformation of magnetic skyrmion due to skyrmion-skyrmion interaction

Zhen-Qian Cui(崔振茜), Wen-Li Yang(杨文力), and Jun-Hui Zheng(郑俊辉)

Chin. Phys. B, 2025, 34 (7): 077502. DOI: 10.1088/1674-1056/adca20

Abstract ( 152 )

HTML ( 0 )

PDF (1575KB) ( 50 )

Understanding skyrmion-skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications. In this article, we investigate the deformation of skyrmions induced by the inter-skyrmion interaction in both static and dynamic scenarios for a two-skyrmion system. In the static case under a pinning magnetic field, the inter-skyrmion interaction energy decreases rapidly with increasing separation between the skyrmions, while their individual sizes grow. The semiaxis ratio of the elliptical skyrmion exhibits non-monotonic behavior, owing to the competition between skyrmion-skyrmion interactions and pinning effects. In dynamic simulations after removing the external pinning field, the two skyrmions spiral away from each other with increasing separation. Following a rapid relaxation period after magnetic field withdrawal, their semiaxis ratio typically increases with distance and the skyrmions gradually approach a perfect circular shape. These findings provide valuable insights into the behavior and interactions of two-skyrmion systems.

Growth diagram of AlN epilayers grown by plasma-assisted molecular beam epitaxy

Huan Liu(刘欢), Pengfei Shao(邵鹏飞), Yu Liu(柳裕), Qi Yao(姚齐), Tao Tao(陶涛), Zili Xie(谢自力), Dunjun Chen(陈敦军), Bin Liu(刘斌), Hai Lu(陆海), Rong Zhang(张荣), and Ke Wang(王科)

Chin. Phys. B, 2025, 34 (7): 077701. DOI: 10.1088/1674-1056/adcb23

Abstract ( 135 )

HTML ( 0 )

PDF (3161KB) ( 72 )

We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy (MBE) on AlN/sapphire templates. The MBE epitaxy of AlN at the low temperature range, which is suitable for AlGaN, encounters significant challenge in preventing Al droplet and pits, since the migration and desorption rate of Al atom are very low. In contrast, by elevating the growth temperature, such a difficulty can be effectively overcome, and we were able to grow AlN films with much improved surface morphology and obtained step flow growth mode without any Al droplets and pits. The cathodoluminescence spectroscopy indicate that the impurity incorporation and defect generation in the AlN epilayers was suppressed by elevating the growth temperature. A systematic investigation on the influence of Al beam flux and growth temperature in a very wide range on the AlN films has been conducted, and a comprehensive growth diagram of MBE AlN has been obtained.

Spatial electron tunneling leads to space-charge-limited current in organic hole transport materials

Shaofeng Chen(陈绍枫), Yanfei Lu(鲁燕飞), Dongcheng Chen(陈东成), and Shi-Jian Su(苏仕健)

Chin. Phys. B, 2025, 34 (7): 078101. DOI: 10.1088/1674-1056/adcb1d

Abstract ( 159 )

HTML ( 0 )

PDF (651KB) ( 55 )

The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices. However, our understanding of the mechanisms behind charge injection remains incomplete. In this study, we explored the hole injection from an indium tin oxide (ITO) electrode into a hole transport layer (HTL) by employing various organic interlayers (ILs) with different ionization potentials (IPs). It was demonstrated that using O$_{2}$ plasma treatment onto an ITO surface and incorporating an interlayer (IL) with a higher IP between the ITO electrode and the HTL can substantially increase the hole current density. This improvement leads to the achievement of barrier-free injection and the establishment of space-charge-limited current. We propose two synergistic mechanisms of spatial electron tunneling that govern the injection characteristics: electron tunneling from the HTL across the IL to the electrode that establishes an electrostatic equilibrium with a zero-injection barrier and an electric-field-induced spatial tunneling effect that occurs during device operation with applying bias. This research offers a strategy to achieve space-charge-limited hole current and provides an explanatory framework for understanding the underlying physics of charge injection.

Single event burnout in SiC MOSFETs induced by nuclear reactions with high-energy oxygen ions

Shi-Wei Zhao(赵世伟), Bing Ye(叶兵), Yu-Zhu Liu(刘郁竹), Xiao-Yu Yan(闫晓宇), Pei-Pei Hu(胡培培), Teng Zhang(张腾), Peng-Fei Zhai(翟鹏飞), Jing-Lai Duan(段敬来), and Jie Liu(刘杰)

Chin. Phys. B, 2025, 34 (7): 078501. DOI: 10.1088/1674-1056/adcd45

Abstract ( 144 )

HTML ( 0 )

PDF (1808KB) ( 210 )

We investigate the impact of high-energy O ions on the occurrence of single-event burnout (SEB) in silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) under various bias conditions. Through a combination of SRIM, GEANT4, and TCAD simulations, we explore the role of secondary ions generated by nuclear reactions between high-energy O ions and SiC materials. These secondary ions, with significantly higher linear energy transfer (LET) values, contribute to electron-hole pair generation, leading to SEB. Our results show that the energy deposition and penetration depth of these secondary ions, especially those with high LET, are sufficient to induce catastrophic SEB in SiC MOSFETs. The study also highlights the critical influence of reverse bias voltage on SEB occurrence and provides insights into the failure mechanisms induced by nuclear reactions with high-energy O ions. This work offers valuable understanding for improving the radiation resistance of SiC-based power devices used in space and high-radiation environments, contributing to the design of more reliable electronics for future space missions.

Unraveling the role of dangling bonds passivation in amorphous Ga₂O₃ for high-performance solar-blind UV detection

Zhengru Li(李正濡), Rui Zhu(朱锐), Huili Liang(梁会力), Shichen Su(宿世臣), and Zengxia Mei(梅增霞)

Chin. Phys. B, 2025, 34 (7): 078502. DOI: 10.1088/1674-1056/adcb24

Abstract ( 167 )

HTML ( 2 )

PDF (4935KB) ( 31 )

Low-cost and large-area uniform amorphous Ga$_{2}$O$_{3}$ (a-Ga$_{2}$O$_{3}$) solar-blind ultraviolet (UV) detectors have garnered significant attention in recent years. Oxygen vacancy (V$_{\rm O}$) defects are generally considered as the predominant defects affecting the detector performance. Reducing V$_{\rm O}$ concentration generally results in both low dark current and low photo current, significantly limiting further improvement of the photo-to-dark current ratio (PDCR) parameter. Herein, a delicately optimized atomic layer deposition (ALD) method is revealed having the capability to break through the trade-off in a-Ga$_{2}$O$_{3}$, achieving both low dark current and high photocurrent simultaneously. For a clear demonstration, a-Ga$_{2}$O$_{3 }$ contrast sample is prepared by magnetron sputtering and compared as well. Combined tests are performed including x-ray photoelectron spectroscopy, photoluminescence, electron paramagnetic resonance and Fourier-transform infrared spectroscopy. It is found that ALD a-Ga$_{2}$O$_{3}$ has a lower V$_{\rm O}$ concentration, but also a lower dangling bonds concentration which are strong non-irradiation recombination centers. Therefore, decrease of dangling bonds is suggested to compensate for the low optical gain induced by low V$_{\rm O}$ concentration and promote the PDCR to $ \sim 2.06 \times 10^{6}$. Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga$_{2}$O$_{3}$ detection performance, offering new insights for further promotion of a-Ga$_{2}$O$_{3 }$ UV detector performance via dual optimization of dangling bonds and V$_{\rm O}$.

Impacts of aging on the entrainment capability of the mammalian circadian system

Ji Zhou(周吉) and Ying Li(李莹)

Chin. Phys. B, 2025, 34 (7): 078701. DOI: 10.1088/1674-1056/adce92

Abstract ( 147 )

HTML ( 0 )

PDF (924KB) ( 61 )

The circadian system of mammals is composed of a hierarchical network of oscillators, including a core clock and peripheral clocks. The core clock receives an external photic signal and transmits it to the peripheral clocks, which, in turn, feed back to the core clock. Aging affects various functions of organisms including the circadian system. Entrainment displays the adaptability of the circadian system to changes in the external environment. However, there is currently no systematic study on the effects of aging on the entrainment capability. To explore the influencing mechanism, we develop a mathematical model of two populations of Goodwin oscillators, which represent the core clock and peripheral clocks. Based on numerical simulations, we conduct a detailed study on the impact of three aging-related factors on the entrainment capability represented by the entrainment range, entrainment time, and entrainment phase. The results indicate that the decrease in the sensitivity of suprachiasmatic nucleus (SCN) to light and the coupling strength from the SCN to the peripheral clocks due to aging increase the phase difference between the core and peripheral clocks, narrow the entrainment range, and prolong the entrainment time. A reduction in the coupling strength within the SCN has little effect on the three aspects mentioned above but increases the entrainment phase. Overall, aging reduces the circadian system's adaptability to the external environment, and the increased entrainment phase may lead to corresponding sleep problems. We also show that modulating the internal coupling strength in the peripheral clocks can mitigate aging effects; this provides an idea for using peripheral clocks to adjust the core clock, while also revealing new insights into the interaction between aging and the elasticity of the circadian system. This mechanism provides theoretical support for treating or alleviating circadian system disorders or sleep problems caused by aging.

Table of contents

Previous issues

1992 - present