Table of contents

24 April 2026, Volume 35 Issue 5 Previous issue   

GENERAL

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Auxiliary-qubit-free quantum approximate optimization algorithm for the minimum dominating set problem Guanghui Li(李广辉), Xiaohui Ni(倪晓慧), Junjian Su(苏俊健), Sujuan Qin(秦素娟), Fenzhuo Guo(郭奋卓), Bingjie Xu(徐兵杰), Wei Huang(黄伟), and Fei Gao(高飞) Chin. Phys. B, 2026, 35 (5):  050304.  DOI: 10.1088/1674-1056/ae5052 Abstract ( 8 )   PDF (2067KB) ( 3 )   Quantum approximate optimization algorithm (QAOA) is a promising framework for solving combinatorial optimization problems on near-term quantum devices. One such problem is the minimum dominating set (MDS), which is known to be NP-hard. Existing QAOA algorithms for this problem typically require numerous auxiliary qubits, increasing circuit overhead and hardware requirements. In this paper, we propose an auxiliary-qubit-free QAOA algorithm based on Hamiltonian evolution (AQFH-QAOA) for the MDS problem. Unlike previous studies that require numerous auxiliary qubits, our algorithm eliminates the need for auxiliary qubits, thereby significantly reducing circuit overhead. In addition, we present an auxiliary-qubit-free optimized implementation of the previously proposed Guerrero’s QAOA algorithm (AQFG-QAOA) by utilizing gate decomposition techniques. Through a detailed analysis of gate complexity, we evaluate the applicability of these two algorithms. Numerical experiments demonstrate that our proposed algorithm achieves competitive solution quality compared with existing QAOA algorithms, making it a promising candidate for implementation on near-term quantum devices.

DATA PAPER

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Curation and featurization of multiple topological materials databases Yuqing He(贺雨晴), Matteo Giantomassi, Gian-Marco Rignanese, and Hongming Weng(翁红明) Chin. Phys. B, 2026, 35 (5):  050701.  DOI: 10.1088/1674-1056/ae2bf2 Abstract ( 6 )   PDF (521KB) ( 1 )   The discovery of topological materials has advanced rapidly due to high-throughput computation and machine learning, but research progress is hampered by inconsistent classification standards and fragmented data resources. Existing databases differ in computational methods, material coverage, and labeling criteria, making it difficult to compare findings across studies. To overcome these challenges, we present a unified topological materials dataset that systematically combines and reconciles two major databases: Materiae and the Topological Materials Database. This dataset provides consistent topological classifications for 35608 materials, accessible through the Materials Galaxy platform for interactive exploration and available for bulk download via MatElab. We describe the featurization methodology that converts crystal structures into 4710 machine-learning-ready descriptors and present a comprehensive analysis of topological material distributions. This work serves as a complete guide for accessing, utilizing, and interpreting this unified resource, designed to enable reproducible machine learning applications and accelerate the discovery of topological materials.

GENERAL

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Physics-informed neural network for material identification via distortion-robust polychromatic x-ray attenuation correction in photon-counting detectors Xin Yan(闫欣), Jie Zhang(张杰), Kai He(何凯), Yiheng Liu(刘毅恒), Yuetong Zhao(赵悦彤), Gang Wang(王刚), Xinlong Chang(常新龙), and Youwei Zhang(张有为) Chin. Phys. B, 2026, 35 (5):  050702.  DOI: 10.1088/1674-1056/ae5a13 Abstract ( 3 )   PDF (747KB) ( 1 )   Spectral distortions in photon-counting detectors (PCDs) fundamentally limit the quantitative accuracy of material identification. While machine learning is used for compensation, current data-driven methods often lack physical constraints, limiting their interpretability and reliability across varying conditions. To address this issue, we propose a physics-informed neural network (PINN) framework that explicitly embeds the Beer-Lambert law into the learning architecture. By integrating an explicit differential layer to extract high-order curvature features from distorted spectra, the model enables direct inference of the effective atomic number and areal density. This approach effectively leverages the $Z$-dependent non-linear profile of the photoelectric effect, even when explicit absorption edges are outside the primary detection window. Simulation results establish a high-precision benchmark for $Z_{\rm{eff}}$ estimation in the target low-$Z$ range (613), with an RMSE of 0.2111. Experimental validation on a CdZnTe-PCD further demonstrates that this accuracy improvement is preserved under realistic pulse pile-up and noise conditions, achieving an RMSE of 0.2457 and an $R^{{2}}$ of 0.9670. Compared with conventional physical correction methods (typically $\pm 0.5$ error margin), the proposed framework provides improved precision, with 92.86 % of $Z_{\rm{eff}}$ estimation errors falling within $\pm 0.4$, corresponding to an approximately 20 % tighter error bound. These results confirm that the proposed framework effectively mitigates spectral distortion, providing a robust, calibration-free solution for precise material identification of low-$Z$ materials in industrial non-destructive testing.

RAPID COMMUNICATION

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Sympathetic cooling of levitated optomechanics through nonreciprocal coupling Jialin Li(李佳霖), Guangyu Zhang(张光宇), and Zhang-Qi Yin(尹璋琦) Chin. Phys. B, 2026, 35 (5):  053701.  DOI: 10.1088/1674-1056/ae4b25 Abstract ( 8 )   PDF (452KB) ( 1 )   Optomechanical cooling of levitated nanoparticles has become an essential topic in modern quantum physics, providing a platform for exploring macroscopic quantum phenomena and high-precision sensing. However, conventional cavity-assisted cooling is fundamentally constrained by cavity dissipation and environmental noise, limiting the attainable minimum temperature. In this work, we propose a non-Hermitian optomechanical cooling scheme through nonreciprocal coupling between two levitated nanoparticles, where one particle is directly cooled by an optical cavity and the other is cooled indirectly through a non-Hermitian interaction. Both analytical solutions and numerical simulations reveal that increasing nonreciprocity enhances directional energy transfer, enabling the target particle to reach a lower phonon occupation than is achievable in conventional cavity cooling. Theoretically, the nonreciprocal coupling scheme achieves a reduction in the steady-state phonon occupation number of the target particle by approximately 80% compared to the conventional cavity cooling limit. This study demonstrates a new cooling mechanism driven by non-Hermitian interactions, offering theoretical guidance for realizing controllable energy flow and deep cooling in levitated optomechanical systems and paving the way for future developments in quantum control and sensing technologies.

ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS

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Generation of wavelength-tunable, bound-state and noise-like pulses in an all-polarization-maintaining laser ring cavity based on nonlinear polarization evolution Yazhou Shi(石亚洲), Ze Li(李泽), and Zhiguo Lv(吕志国) Chin. Phys. B, 2026, 35 (5):  054202.  DOI: 10.1088/1674-1056/ae15f3 Abstract ( 10 )   PDF (1103KB) ( 6 )   Wavelength-tunable fiber lasers are of great interest due to their ability to meet the needs of multiple wavelengths simultaneously. In this work, a tuned spectrum of 13 nm (1564.5–1577.5 nm) is obtained using the nonlinear polarization evolution (NPE) technique by adjusting the polarization controller (PC) to use six segments of polarization-maintaining (PM) fibers with specific splicing angles in an all-PM ring cavity. The output pulse characteristics are also measured, and the signal-to-noise ratio (SNR) is greater than 74 dB. A soliton pulse with a pulse width of about 469 fs is generated at a repetition frequency of 14.12 MHz, which demonstrates the excellent performance of the fiber laser. In addition, by changing the cavity parameters and adjusting the PC, bound states and noise-like pulses are generated in the six-segment structure. So far, the generation of these two types of pulses has not been reported in other PM NPE structured fiber lasers, and the formation mechanism may be related to the complex nonlinear interactions in mode-locked fiber lasers. Our work demonstrates the potential of the PM NPE structure for applications in broad spectral tuning as well as in the generation of multiple pulse types.

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Numerical simulation of the Innoslab laser amplifier based on Yb:YAG crystal Xiang-Yu Qiao(乔向宇), Qi Liu(刘齐), Xiao-Wei Xing(邢笑伟), Yang-Tian Liu(刘扬天), Rui-Qi Liu(刘瑞琪), Xi-Wei Huang(黄玺玮), Hao-Yu Wang(王浩宇), and Wen-Jun Liu(刘文军) Chin. Phys. B, 2026, 35 (5):  054205.  DOI: 10.1088/1674-1056/ae5175 Abstract ( 15 )   PDF (1016KB) ( 5 )   A numerical simulation model is developed for a Yb:YAG Innoslab amplifier. By unfolding the multi-pass folded optical path into a one-dimensional slicing model, the model employs differential iterative calculations. This approach enables high-precision characterization of key physical processes, including spot size evolution, pump-laser saturated absorption distribution, the Yb:YAG reabsorption effect, and the spatial dynamic coupling between the pump and seed beams. Notably, a novel correction mechanism for the small-signal gain coefficient in the overlap regions of adjacent passes is proposed for the first time, specifically addressing the energy re-extraction issue neglected in previous models. This correction significantly enhances the computational accuracy and physical fidelity of the model. Validations against existing experimental data demonstrate high consistency between simulated and measured results, confirming the model’s excellent applicability and reliability. This work provides a reliable theoretical basis for the structural optimization and parameter tuning of Innoslab amplifiers.

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Generalized likelihood ratio detector for forward scattering detection in uncertain shallow-water environments Jiahui Luo(罗嘉辉), Chao Sun(孙超), Mingyang Li(李明杨), and Shaodong Zhang(张少东) Chin. Phys. B, 2026, 35 (5):  054303.  DOI: 10.1088/1674-1056/ae118f Abstract ( 1 )   PDF (1054KB) ( 1 )   Forward scattering detection in shallow-water environments presents many challenges, particularly the issues of environmental uncertainties and direct blast, which is an intense sound wave that propagates directly from the source to the receiver without interaction with the target. In this paper, we account for environmental uncertainties and extend the generalized likelihood ratio detector (GLRD) for forward scattering detection in a known environment to uncertain environments. In a suitable bistatic sonar configuration where the source is positioned on the broadside of a large aperture horizontal linear array (HLA), the GLRD exhibits good resistance to direct blast. Moreover, the GLRD demonstrates a certain degree of robustness against environmental uncertainties, particularly when the sampling uncertainty sets of the direct blast/signal wavefront are large enough — including both the real direct blast wavefront and the real signal wavefront. Despite facing the challenge of direct blast in forward scattering detection, the GLRD still performs well in this scenario and demonstrates its effectiveness as a method for forward scattering detection in uncertain shallow-water environments.

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Open thermal cloak based on active thermal metasurfaces Bao-Quan Hou(侯宝泉), Fei Sun(孙非), Yi-Chao Liu(刘一超), Jia-Peng Wang(王嘉鹏), Ya-Ru Feng(冯亚茹), Bin-Zhao Cao(曹斌照), Hong-Ming Fei(费宏明), and Jie Wu(武洁) Chin. Phys. B, 2026, 35 (5):  054401.  DOI: 10.1088/1674-1056/ae48bf Abstract ( 19 )   PDF (6313KB) ( 7 )   The enclosed configuration of conventional thermal cloaks prevents the passage of matter across their boundaries. To overcome this limitation, we propose an open thermal cloak (OTC) that simultaneously provides effective thermal cloaking and incorporates a functional exit that allows unimpeded passage and exchange of matter. The OTC integrates a closed thermal cloak with an exit (CTCE) and a thermal shifter designed via coordinate transformation. The thermal shifter compensates for performance degradation caused by the exit by transferring the thermal regulation function of the removed segment back to the exit location, using a material with equivalent negative thermal conductivity derived from transformation thermotics. For practical implementation, this idealized material is replaced with discrete active thermal metasurfaces (ATMs) at the boundary to replicate the required heat flux conditions. Numerical simulations show that the ATM-based OTC exhibits excellent cloaking performance under varying heat flow directions and across exits of different sizes and shapes, maintaining background temperature field integrity and a near-uniform temperature distribution inside the protected region. The average temperature disturbance induced is significantly lower than that of CTCE and a directly exposed object, with performance approaching that of an ideal closed thermal cloak (CTC). This work breaks the enclosure limitation of traditional thermal cloaks and shows promise for infrared thermal protection of underground shelters and the thermal management of heat-sensitive electronics.

SPECIAL TOPIC — John Tse: Pioneer in high-pressure materials science

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Structural stability and mechanical properties of TiB6: A CALYPSO-guided exploration for superhard applications Bo Sun(孙博), Yutong Zou(邹雨桐), Tao Wang(王淘), Yujia Wang(王雨佳), Jinyu Liu(刘金禹), Lili Gao(高丽丽), Meiguang Zhang(张美光), and Miao Zhang(张淼) Chin. Phys. B, 2026, 35 (5):  056105.  DOI: 10.1088/1674-1056/adfb59 Abstract ( 4 )   PDF (1640KB) ( 1 )   Titanium-boron (Ti-B) compounds exhibit great promise as superhard materials due to titanium's low atomic mass and abundant valence electrons. In this work, we systematically investigated the crystal structures of TiB6 under pressures ranging from 0-100 GPa using the CALYPSO algorithm combined with first-principles calculations. Phonon dispersion analysis and elastic-constant evaluations confirm the dynamic and mechanical stability of five predicted TiB6 structures. Notably, the α-Amm2-TiB6 structure was predicted to have a remarkable Vickers hardness of 56 GPa, as estimated by Chen's empirical model. All five structures are thermodynamically stable under ambient conditions, suggesting viable synthetic pathways. Their outstanding bulk moduli and ultrahigh hardness further classify them as potential incompressible and superhard materials. These theoretical insights lay a robust foundation for future experimental synthesis efforts.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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Visible transparent β-Ga2O3 solar-blind UV high-performance photodetector for stable high-temperature operation Chao Zhang(张超), Jinpeng Dong(董瑾鹏), Gang Li(李刚), Yida Guan(管艺达), Jiahao Zhang(张嘉豪), Qingyu Wang(王清玉), Zhilin Wang(王志林), Duo Sun(孙多), Yue Sun(孙悦), and Lili Wang(王丽丽) Chin. Phys. B, 2026, 35 (5):  056106.  DOI: 10.1088/1674-1056/ae311f Abstract ( 5 )   PDF (983KB) ( 1 )   Transparent ultraviolet (UV) photodetectors have garnered significant interest due to their promising applications in integrated transparent electronics. In this work, a visible transparent solar-blind ultraviolet photodetector with stable crystalline ITO electrodes based on a $\beta$-Ga$_{2}$O$_{3}$ film has been fabricated and characterized from room temperature to 400 $^\circ$C. The results demonstrate that the device maintains excellent thermal stability even at high temperatures up to 400 $^\circ$C and achieves outstanding performance metrics, including a low dark current of 7.5 pA, a superb UV/visible rejection ratio of $7.8 \times 10^{5}$, and a large detectivity of $1.3 \times 10^{15}$ Jones. This overall performance surpasses that of most other reported Ga$_{2}$O$_{3}$-based transparent UV photodetectors. Therefore, the fabricated high-performance transparent $\beta $-Ga$_{2}$O$_{3}$ solar-blind UV photodetector demonstrates considerable potential for applications in advanced transparent electronics under extreme environments.

SPECIAL TOPIC — Structures and properties of materials under high pressure

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Pressure-tuned structure and superconductivity in 2H-NbSe2 Chen-Yi Li(李晨一), Zong-Lun Li(李宗伦), Hui Tian(田辉), Guang-Rui Gu(顾广瑞), Quan-Jun Li(李全军), and Xue-Ting Zhang(张雪婷) Chin. Phys. B, 2026, 35 (5):  056401.  DOI: 10.1088/1674-1056/ae40db Abstract ( 7 )   PDF (3711KB) ( 1 )   The structural and superconducting properties of 2H-NbSe$_{2}$ were systematically investigated under pressure up to 55.4 GPa using high-pressure electrical transport measurements, synchrotron radiation x-ray diffraction, and theoretical calculations. With increasing pressure, the enhanced interlayer coupling of 2H-NbSe$_{2}$ induces a structural transition from quasi-two dimensional to three dimensional. Meanwhile, accompanied by Fermi surface reconstruction, 2H-NbSe$_{2}$ exhibits a characteristic dome-shaped superconducting behavior, which provides valuable insights into the relationship between its superconducting properties and the structural transition.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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Message passing method for social contagion in hypergraphs Hui Leng(冷卉), Zhao-Yan Wu(吴召艳), and Rong Wang(王荣) Chin. Phys. B, 2026, 35 (5):  056403.  DOI: 10.1088/1674-1056/ae5c73 Abstract ( 3 )   PDF (1173KB) ( 1 )   The emergence of hypergraphs has solved the problem that the interactions between nodes are insufficient to describe the complex relationships among multiple individuals. In this paper, we model social contagion with the reinforcement effect on hypergraphs, where hyperedges disseminate information to nodes, and nodes upload information to hyperedges. In order to reduce the complexity of high-order interactions on the propagation, hypergraphs are mapped to factor graphs, where hyperedges are encoded to factor nodes, and the connection between a node and a factor node indicates that the node is located in the hyperedge. Taking into account the heterogeneity of nodes and hyperedges, we establish the message passing evolution equations about each node based on the factor graph. Finally, we carry out numerical simulations by iterating the message passing equations. We find that the probability of the adopted state decreases before the outbreak of social contagion, and the final adopting scale suddenly increases as the transmission rates increase, which are caused by the combined action of high-order interactions and the social reinforcement effect. Significantly, the final adopting scale presents a step-like variation when the adopting threshold of hyperedges changes.

RAPID COMMUNICATION

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Formation of crystalline Si9C15 nano-islands and Si9C15/graphene heterostructures on Ru(0001) Lijing Huang(黄丽静), Yumeng Li(李雨萌), Hongqin Xiao(肖洪钦), Yuxuan He(何昱萱), Geng Li(李更), and Hong-Jun Gao(高鸿钧) Chin. Phys. B, 2026, 35 (5):  056801.  DOI: 10.1088/1674-1056/ae4c6f Abstract ( 6 )   PDF (1112KB) ( 2 )   Two-dimensional silicon carbides have attracted increasing interest due to their highly tunable band structures and rich physical properties. Among them, Si$_{9}$C$_{15}$ is particularly notable for its intrinsic auxeticity, strongly anisotropic carrier mobility, and pronounced optical and thermoelectric responses. However, the controlled growth of Si$_{9}$C$_{15}$ nano-islands has remained a challenge. Here, we report a novel growth technique for Si$_{9}$C$_{15}$ nano-islands. By exploiting the mild segregation of carbon atoms from a Ru(0001) substrate, we fabricate discrete, crystalline Si$_{9}$C$_{15}$ nano-islands at temperatures as low as $\sim 400 ^\circ$C. Spectroscopic measurements reveal a spatial modulation of the local work function across the nano-island, which we attribute to the periodic potential landscape of the Si$_{9}$C$_{15}$ lattice. Furthermore, we demonstrate that this island morphology enables the construction of Si$_{9}$C$_{15}$/graphene lateral heterostructures. Our work establishes a new pathway for fabricating Si$_{9}$C$_{15}$ nanostructures as well as the heterostructures.

SPECIAL TOPIC — Exciton Physics: Fundamentals, materials and devices

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Photoexcitation of the one-dimensional extended Peierls-Hubbard model at quarter-filling Yu-Peng Li(李昱澎), Yu-Chang Liu(刘羽畅), Yu-Zhuo Zhao(赵玉卓), Hantao Lu(陆汉涛), and Can Shao(邵灿) Chin. Phys. B, 2026, 35 (5):  057104.  DOI: 10.1088/1674-1056/ae27af Abstract ( 6 )   PDF (446KB) ( 3 )   Utilizing the time-dependent Lanczos method, we investigate the photoexcitation dynamics of the one-dimensional (1D) extended Peierls–Hubbard model at quarter filling. In equilibrium, it is well established that introducing the nearest-neighbour interaction V into the 1D Peierls–Hubbard model can lead to the formation of Mott–Hubbard excitons, which exhibit a characteristic frequency in the optical conductivity that is lower than the Mott gap. Ultrafast photoexcitation of this model gives rise to a transient metallic state for V < 2, characterized by several features, including a zero-frequency Drude peak in the post-pump optical conductivity, an increase in the density of charge carriers, and enhanced electron hopping between dimers. In contrast, when V ≥ 2, this metallic state is no longer observed, as photoinduced carriers bind to form excitons, thereby inhibiting metallic behavior. These results highlight a parallel between the optical excitation of the 1D extended Peierls–Hubbard model at quarter filling and that of the 1D extended Hubbard model at half filling, suggesting a universal mechanism governing their photoinduced responses.

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Power-law scaling of low-temperature effective mass in La3ScBi5 Yi-Ran Li(李祎冉), Yong-Hao Gao(高永豪), Xiao-Qin Lu(卢小琴), Ping Su(苏平), Hui Liang(梁慧), Ying Zhou(周颖), Dan-Dan Wu(吴丹丹), Yan Sun(孙燕), Qiu-Ju Li(李秋菊), Jin-Yu Liu(刘金雨), Shou-Guo Wang(王守国), Gang Chen(陈钢), Tian-Long Xia(夏天龙), Na Li(李娜), Xue-Feng Sun(孙学峰), and Yi-Yan Wang(王义炎) Chin. Phys. B, 2026, 35 (5):  057107.  DOI: 10.1088/1674-1056/ae39d1 Abstract ( 6 )   PDF (1330KB) ( 2 )   The variation of the effective mass $m^*$ of carrier is often overlooked in experimental studies on quantum oscillations and Kohler's rule. Here, we report the magnetotransport properties of La$_3$ScBi$_5$ and reveal the changing $m^*$ in it. The temperature and magnetic field dependence of $m^*$ follows the power-law scaling behavior at low temperature and leads to the failure of conventional analysis, which should not be ignored. In the analysis of the thermal factor and Dingle plot of de Haas-van Alphen oscillation in La$_3$ScBi$_5$, satisfactory fitting results can be obtained after considering the correction of $m^*$. We have also applied this method to Sr$_{1-y}$Mn$_{1-z}$Sb$_2$, solving the remaining fitting problem in previous reports. Moreover, the magnetoresistance (MR) of La$_3$ScBi$_5$ has been found to violate Kohler's rule. Although the extended Kohler's rule is applicable to high-temperature MR data, it does not scale the low-temperature data well. We further modified the extended Kohler's rule by introducing $m^*$, and subsequently scaled the low-temperature MR data well. Our study emphasizes the importance of considering the variation of $m^*$ in the analysis of quantum oscillations and Kohler's rule, and provides a method for extracting the temperature and magnetic field dependence of $m^*$ through quantum oscillations, which is very beneficial for the data analysis of other materials in the future.

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Design and optimization of area-selective carrier modulation in β-Ga2O3 through high temperature oxygen annealing Qiuyan Li(李秋艳), Qiming He(何启鸣), Jinyang Liu(刘金杨), Xuanze Zhou(周选择), Guangwei Xu(徐光伟), and Shibing Long(龙世兵) Chin. Phys. B, 2026, 35 (5):  057108.  DOI: 10.1088/1674-1056/ae3c94 Abstract ( 1 )   PDF (760KB) ( 1 )   Carrier modulation in beta-gallium oxide ($\beta $-Ga$_{2}$O$_{3}$) films through an oxygen annealing method is systematically investigated, including annealing time and annealing cap layer (ACL) design. Capacitance-voltage measurement conducted on vertical SBD structures was used to evaluate the carrier concentration after annealing. The formation of a “surface layer” may suppress the diffusion of oxygen species as the annealing time increases. An 8-hour annealing time resulted in a carrier modulation with an approximately 3-μm-deep low-carrier-concentration layer. The annealing cap layer, consisting of poly-Si and SiO$_{2}$, was deposited and patterned to achieve area-selective carrier modulation in $\beta $-Ga$_{2}$O$_{3}$. The effective thickness of poly-Si for blocking oxygen diffusion was confirmed by scanning electron microscopy (SEM) for the first time. A definite thickness of SiO$_{2}$ served as both etching stop layer and lift-off layer for poly-Si. According to simulation results, the non-ideal surface caused extra high peak electric field in the $\beta $-Ga$_{2}$O$_{3}$ device. A combination of an optimized dry etching method and low-compressive-stress deposition technology was employed to eliminate the bird's beak-like shape structure that appeared at the edges of the patterns and bulges on the $\beta $-Ga$_{2}$O$_{3}$ surface after annealing. The feasibility of the carrier modulation technology enables the diversity of $\beta $-Ga$_{2}$O$_{3}$ devices fabrication.

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Large anomalous Hall and Nernst effect in the breathing kagome ferromagnet NdCrGe3 Yang Liu(刘洋), Meng Lyu(吕孟), Junyan Liu(刘俊艳), Yibo Wang(王一博), Jinying Yang(杨金颖), Binbin Wang(王彬彬), Xiyang Li(李西阳), and Enke Liu(刘恩克) Chin. Phys. B, 2026, 35 (5):  057201.  DOI: 10.1088/1674-1056/ae44f0 Abstract ( 1 )   PDF (2003KB) ( 1 )   The anomalous Hall and Nernst effects provide critical probes for investigating the Berry-curvature-related electronic band characteristics in magnetic materials. In this study, we conducted a comprehensive investigation into the magnetic, electrical, and thermal transport properties of NdCrGe$_{3}$ single crystals with a Ge-based breathing kagome lattice. This compound undergoes a ferromagnetic transition at 128 K, and magnetic ordering of the Nd sublattice emerges below 100 K. Transport measurements indicate that NdCrGe$_{3}$ manifests large anomalous Hall conductivity with $\sigma_{xy}^{{\rm A}} \approx 380 \Omega ^{-1}\cdot$cm$^{-1}$ at low temperatures and an anomalous Nernst coefficient with $\vert S_{xy}^{{\rm A-max}}\vert = 0.74$ μV/K at 100 K. Scaling analysis reveals that NdCrGe$_{3}$ exhibits large intrinsic anomalous Hall conductivity of $\sim 260 \Omega^{-1}\cdot$cm$^{-1}$ and falls within the intrinsic regime of the unified model. Furthermore, the anomalous Nernst coefficient breaks down the scaling relationship with magnetization observed in conventional ferromagnets, while the anomalous Nernst conductivity manifests a scaling behavior of $T \ln T$. These results demonstrate that the anomalous transverse transport properties of NdCrGe$_{3}$ are predominantly governed by the intrinsic Berry mechanism.

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Quantum anomalous Hall effect with tunable Chern numbers induced by d-wave sublattice-staggered altermagnetism Lizhou Liu(刘立周) and Qing-Feng Sun(孙庆丰) Chin. Phys. B, 2026, 35 (5):  057301.  DOI: 10.1088/1674-1056/ae42bb Abstract ( 9 )   PDF (1089KB) ( 1 )   We construct a minimal spinful tight-binding model on a square lattice, where a d-wave sublattice-staggered altermagnetism drives the quantum anomalous Hall effect. Here the exchange field is staggered between the two sublattices, where it takes opposite signs on $A$ and $B$ described by the Pauli matrix $\tau_z$. The resulting insulating phases host tunable Chern numbers $\mathcal{C}=\pm1$ and $\mathcal{C}=\pm2$, controlled by the staggered exchange strength and the sublattice-staggered potential. We determine the complete phase diagram, identify valley-resolved band inversions at the $X$ and $Y$ points in the Brillouin zone, and demonstrate chiral edge states together with quantized two-terminal conductance plateaus. Our work provides a simple route to realizing the quantum anomalous Hall effect in compensated magnets via a d-wave sublattice-staggered altermagnetism.

SPECIAL TOPIC — John Tse: Pioneer in high-pressure materials science

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Unveiling the superconducting mechanism and phase stability of LaB2H8 under pressure Jirun Wu(吴际润), Zefang Wang(王泽方), Xin Zhong(钟鑫), and Hanyu Liu(刘寒雨) Chin. Phys. B, 2026, 35 (5):  057401.  DOI: 10.1088/1674-1056/ae39d0 Abstract ( 7 )   PDF (5796KB) ( 0 )   The recent synthesis of the superhydride LaB$_{2}$H$_{8}$, which exhibits a superconducting transition temperature ($T_{\rm c}$) of 106 K at 90 GPa, offers a promising avenue for exploring high-temperature superconductivity. However, the underlying superconducting mechanism remains elusive. Here, we employ first-principles calculations to systematically investigate the electronic structure, lattice dynamics, electron-phonon coupling, and molecular-orbital features of LaB$_{2}$H$_{8}$. Our analysis reveals that the structural stability and metallic conductivity primarily originate from the covalent B-H bonds within the B$_{2}$H$_{8}$ units. Furthermore, we observe a pronounced softening of low-frequency phonons at elevated pressures, which induces strong electron-phonon coupling and serves as the key driving force for superconductivity in this system. This work not only elucidates the superconducting mechanism in LaB$_{2}$H$_{8}$ but also highlights the importance of covalent hydrogen-based motifs in designing new high-$T_{\rm c}$ superconductors.

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Superconductivity in bulk 2H-MoS2 via carrier doping Mingshu Tan(谭明蜀), Helin Mei(梅贺林), Keyi Li(李可意), Wei Ren(任玮), Xueying Ma(马雪英), Shaoshuai Hou(侯少帅), Feng Jin(金峰), Anmin Zhang(张安民), and Qingming Zhang(张清明) Chin. Phys. B, 2026, 35 (5):  057403.  DOI: 10.1088/1674-1056/ae3c93 Abstract ( 6 )   PDF (1416KB) ( 1 )   As a prototypical transition metal dichalcogenide (TMD) semiconductor, MoS$_{2}$ exhibits diverse tunable electronic properties in low-dimensional systems, such as Ising superconductivity and charge density waves (CDWs). However, the intrinsic superconductivity of bulk MoS$_{2}$ remains underexplored. Here, we demonstrate carrier doping in bulk 2H-MoS$_2$ using an ionic-liquid-gating method, resulting in anisotropic bulk superconductivity with a critical temperature $T_{\rm c}$ of 3.2 K. Notably, the superconducting transition in the bulk requires the lowest critical carrier density ($\sim 10^{13}$ cm$^{-2}$) among all the reported superconducting MoS$_{2}$ systems, while exhibiting a higher $T_{\rm c}$ than typically observed in monolayers. The electron-phonon coupling (EPC) constant extracted from Raman spectroscopy yields a calculated $T_{\rm c}$ consistent with the experimental observations, in agreement with the mechanism established in monolayer MoS$_{2}$. We attribute these observations to the Fermi level preferentially crossing the lower-energy $Q$ point in the bulk, which facilitates superconducting pairing. The results provide deeper insights into the superconducting mechanism in bulk 2H-MoS$_{2}$.

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Response of the C4 magnetic phase in iron-based superconductors to electronic structure tuning via doping/uniaxial strain Li-Li Meng(孟丽丽), Ting-Ting Han(韩婷婷), Yu-Jing Ren(任宇靖), Jing-Zhi Chen(陈景芝), Peng-Hao Yuan(袁鹏浩), and Yan Zhang(张焱) Chin. Phys. B, 2026, 35 (5):  057404.  DOI: 10.1088/1674-1056/ae3c8e Abstract ( 8 )   PDF (1413KB) ( 2 )   Elucidating how magnetic interactions are established in high-temperature superconductors is crucial for resolving the long-standing puzzle of the superconducting pairing mechanism. However, for iron-based superconductors, due to the diversity of their magnetic and electronic structures, the mechanism of magnetic interactions remains controversial. Here, we employed in-situ alkali-metal deposition and uniaxial strain to tune the four-fold (C4) magnetic phase in Sr$_{0.64}$Na$_{0.36}$Fe$_{2}$As$_{2}$ and utilized angle-resolved photoemission spectroscopy (ARPES) to probe the response of its electronic structure. We found that the alkali-metal deposition suppresses the C4 magnetic phase effectively, driving the system into a stripe spin density wave phase with two-fold rotational (C2) symmetry. Counterintuitively, the uniaxial strain that naturally breaks the C4 rotational symmetry of the lattice exerts only a limited suppressive effect on the C4 magnetic phase. While the sensitivity of C4 magnetic phase to electron doping implies that the orbital selectivity of Fermi surface nesting plays a critical role in determining the magnetic configuration, validating the contribution of itinerant electrons in mediating the magnetic fluctuations, the insensitivity of the C4 magnetic phase to uniaxial strain suggests that the nematic order exhibits no intermediate correlation with the magnetism in iron-based superconductors. Our results provide crucial clues for a comprehensive understanding of the complex phase diagram of iron-based superconductors.

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Exact ground state properties of the t-j model with open boundary conditions Pei Sun(孙佩), Yuanyuan Lei(雷瑗瑗), Xiaotian Xu(许小甜), Junpeng Cao(曹俊鹏), Tao Yang(杨涛), and Wen-Li Yang(杨文力) Chin. Phys. B, 2026, 35 (5):  057501.  DOI: 10.1088/1674-1056/ae37fa Abstract ( 12 )   PDF (324KB) ( 2 )   We develop a new method to study the ground state energy of the one-dimensional supersymmetric t-J model with open boundary conditions. The eigenvalues of the nested transfer matrix are characterized by the zero roots of corresponding polynomials instead of the T-Q relation and Bethe roots. The distribution of zero roots at the ground state is studied. We find that the zero roots form two-string pairs, finite pure real and pure imaginary boundary strings. Based on the distribution of zero roots, we obtain the ground state energy of the system in the thermodynamic limit.

SPECIAL TOPIC — Structures and properties of materials under high pressure

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Optical properties of five-layer and ten-layer CrI3 films under high pressure: Insights from in situ Raman and UV–visible spectroscopy Zhipeng Yan(闫志鹏), Xiaodong Yao(姚晓东), Guangyang Dai(代光阳), Chenkai Li(李辰恺), Qunfei Zheng(郑群飞), Jun Han(韩军), Ying Liu(刘影), and Xiaowei Sun(孙小伟) Chin. Phys. B, 2026, 35 (5):  057801.  DOI: 10.1088/1674-1056/ae40d9 Abstract ( 11 )   PDF (824KB) ( 3 )   The two-dimensional van der Waals ferromagnetic semiconductor CrI$_{3}$ provides an ideal platform for exploring the interplay among structural, electronic and magnetic degrees of freedom. In this work, we systematically investigate the thickness-dependent optical properties of five-layer and ten-layer CrI$_{3}$ under hydrostatic pressure up to 27.9 GPa by in situ Raman and UV-visible absorption spectroscopy. All A$_{\rm g}$ Raman modes exhibit a continuous blueshift with increasing pressure. The low-frequency modes ($\mathrm{A}_{\mathrm{g}}^{{1}}$-$\mathrm{A}_{\mathrm{g}}^{{3}}$) are mainly associated with enhanced interlayer coupling, whereas the high-frequency modes ($\mathrm{A}_{\mathrm{g}}^{{4}}$-$\mathrm{A}_{\mathrm{g}}^{{6}}$) reflect the suppression of surface vibrations. The Raman modes disappear at approximately 4.9 GPa for the five-layer sample and 11.2 GPa for the ten-layer sample, indicating a stronger strain sensitivity in thinner CrI$_{3}$. Optical absorption measurements show a pronounced redshift of the absorption edge, accompanied by bandgap narrowing from 2.26 eV to 1.26 eV in five-layer CrI$_{3}$. At comparable pressures, the five-layer sample consistently exhibits a wider bandgap than the ten-layer one, which is attributed to quantum confinement effects and reduced interlayer hybridization. Above 12.7 GPa, the bandgap reduction becomes less pronounced, probably due to enhanced Cr 3d/I 5p orbital overlap and strengthened superexchange interactions. These results reveal a clear layer-dependent structure-electronic coupling in CrI$_{3}$ under compression and provide useful insights into pressure modulation of van der Waals magnetic semiconductors.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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Tunable multi-frequency exceptional points in non-Hermitian terahertz metasurfaces Xiang Hou(侯翔), Fangze Deng(邓方泽), Zhihua Han(韩志华), Yumeng Ma(马宇萌), Chenglong Wang(王成龙), Yuchao Li(李玉超), Keke Cheng(程可可), Ke Ma(马克), Yansheng Shao(邵延胜), Ruidan Zhou(周瑞丹), Yuping Zhang(张玉萍), Meng Liu(刘蒙), and Huiyun Zhang(张会云) Chin. Phys. B, 2026, 35 (5):  057802.  DOI: 10.1088/1674-1056/ae12d8 Abstract ( 9 )   PDF (1774KB) ( 2 )   Exceptional points (EPs) in non-Hermitian metasurfaces have garnered considerable attention due to their unique advantages in cutting-edge applications such as ultra-sensitive sensing and unidirectional reflectionlessness. However, existing studies on metasurfaces employing both active and passive tuning mechanisms can only observe a single EP, which fails to meet the requirements for multi-frequency responses or multifunctional integration, thus limiting the enhancement of device performance. In this study, we design a terahertz (THz) non-Hermitian metasurface device that is actively tuned by the phase-change material VO$_{2}$. By keeping the geometric dimensions of the device unchanged, we achieve the simultaneous induction and detection of multi-frequency EPs at multiple frequency points. Through the regulation of VO$_{2}$ conductivity, the gain-loss distribution of the system can be continuously controlled, leading to the degeneracy of eigenvalues and eigenstates across multiple discrete frequency bands, thereby forming multi-frequency EPs. Furthermore, the design of chiral structures demonstrates that, under identical conductivity conditions, the eigenstates of the original metasurface structure and its chiral counterpart can degenerate into circularly polarized states with opposite rotations, enabling the switching of polarization chirality. These results illustrate that the deep integration of phase-change materials, non-Hermitian photonics, and electromagnetic manipulation in metasurfaces provides a novel design paradigm for the dynamic regulation of multi-frequency EPs and circular polarization control, laying a foundation for the development of high-performance and multifunctional integrated photonic platforms in the THz regime.

INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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Improved stability of amorphous InGaZnO4 thin-film transistors under negative bias illumination stress with the incorporation of fluorine passivation and metal shielding lines Yuhan Feng(冯雨涵), Nannan Lv(吕楠楠), Huaisheng Wang(王槐生), Mingxiang Wang(王明湘), and Dongli Zhang(张冬利) Chin. Phys. B, 2026, 35 (5):  058103.  DOI: 10.1088/1674-1056/ae40da Abstract ( 4 )   PDF (612KB) ( 1 )   The instability phenomenon under negative bias illumination stress (NBIS) remains a major challenge for the application of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) in active-matrix displays. In this paper, we employ fluorine plasma treatment and a segmented metal cover line approach to enhance the stability of elevated metal metal-oxide (EMMO) a-IGZO TFTs under NBIS. At room temperature, after 15 minutes of fluorine treatment, $\Delta V_{\rm ON}$ decreases from 5.53 V to 2.02 V. This improvement is mainly attributed to the fact that fluorine atoms fill the ionized oxygen vacancies in a-IGZO, thereby reducing the density of defect states in the channel. Further adding 2.0 μm wide metal-covered wires reduces the $\Delta V_{\rm ON}$ to 0.35 V. Under 80 ${^\circ}$C NBIS, the $\Delta V_{\rm ON}$ is limited to 3.79 V. This improvement is mainly attributed to the light-shielding effect of the metal lines and the passivation of oxygen vacancies by fluorine, thereby enhancing device stability under NBIS.

RAPID COMMUNICATION

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Thermally-enhanced charge collection boosts photoelectrochemical performance of hematite Yujie Wang(王玉杰), Xu Cheng(程旭), Jialin Shao(邵嘉琳), Xugang Qi(漆旭刚), Jia Zhao(赵嘉), Lu Yang(杨露), Youwei Zhang(张有为), Bonan Zhu(朱博南), and Zemin Zhang(张泽民) Chin. Phys. B, 2026, 35 (5):  058201.  DOI: 10.1088/1674-1056/ae37fc Abstract ( 10 )   PDF (1604KB) ( 2 )   The application of transition metal oxides in optoelectronics holds significant promise. However, their performance is often limited by small polaron hopping, a charge transport mechanism that reduces carrier mobility and collection efficiency. Therefore, improving small polaron hopping is crucial for enhancing charge collection. In this work, we propose a direct approach to effectively enhance the photoelectrochemical (PEC) performance of hematite by leveraging the thermal nature of polaron hopping. As a result, a photocurrent density of 4.53 mA/cm$^{2}$ at 1.23 V vs. RHE was achieved by heating the photoanode to 70 ${^\circ}$C. By combining carrier dynamics analysis with charge collection modeling, we demonstrate that heating facilitates small polaron hopping, thereby increasing carrier mobility and improving the collection efficiency of hematite photoanodes. Our work provides clear explanations of the thermal-activated small polaron hopping mechanism, offering a simple yet effective strategy for enhancing the PEC performance of transition metal oxides.

DATA PAPER

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HiFAST: An H I data calibration and imaging pipeline for the FAST IV: The stray-radiation correction Qing-Ze Chen(陈箐泽), Jie Wang(王杰), Ying-Jie Jing(景英杰), Li-Gang Hou(侯立刚), Chen Xu(徐晨), Tian-Tian Liang(梁甜甜), Xu-Yang Gao(高旭阳), Jin-Lin Han(韩金林), Zi-Ming Liu(刘孜铭), Bin Liu(刘彬), Chuan-Peng Zhang(张传鹏), Heng-Qian Gan(甘恒谦), Ming Zhu(朱明), Yan Zhu(朱岩), and Peng Jiang(姜鹏) Chin. Phys. B, 2026, 35 (5):  059501.  DOI: 10.1088/1674-1056/ae4b27 Abstract ( 5 )   PDF (849KB) ( 1 )   Stray radiation is a considerable challenge for radio telescopes, requiring careful assessment of its effects. This is crucial when the strong background flux from side lobes significantly affects the total flux, especially for extended sources. In this study, we introduced the beam pattern of the L-band receiver on the Five-hundred-meter Aperture Spherical Telescope (FAST), covering various frequencies based on recent observations. We discovered that the main beam efficiency of all beams exceeds 90 % throughout the L band frequencies, with efficiency decreasing slowly as frequency increases. Subsequently, we developed a module to mitigate stray radiation effects, incorporating it into FAST's standard H\textsc{i} data reduction process, referred to as HiFAST. Our analysis shows that side lobe flux's influence, particularly for extended sources with significant surface density gradients, necessitates detailed evaluation. Corrections for the extended M33 galaxy can reach up to 20 %. Moreover, the pattern data presented here is vital for studying H\textsc{i} intensity maps at high redshift. The module, along with HiFAST and beam pattern data across 15 frequency bins, can be accessed at \href{https://hifast.readthedocs.io}{https://hifast.readthedocs.io}. The datasets of beam pattern presented in this paper are openly available at \href{https://doi.org/10.57760/sciencedb.j00113.00266}{https://doi.org/10.57760/sciencedb.j00113.00266}.