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Microwave absorption properties regulation and bandwidth formula of oriented Y2Fe17N3-δ@SiO2/PU composite synthesized by reduction-diffusion method Hao Wang(王浩), Liang Qiao(乔亮), Zu-Ying Zheng(郑祖应), Hong-Bo Hao(郝宏波), Tao Wang(王涛), Zheng Yang(杨正), and Fa-Shen Li(李发伸) Chin. Phys. B, 2022, 31 (11): 114206.   DOI: 10.1088/1674-1056/ac81ac Abstract （182）   HTML （10）    PDF （3360KB）（145）       Knowledge map    As concepts closely related to microwave absorption properties, impedance matching and phase matching were rarely combined with material parameters to regulate properties and explore related mechanisms. In this work, reduction-diffusion method was innovatively applied to synthesize rare earth alloy Y$_{2}$Fe$_{17}$. In order to regulate the electromagnetic parameters of absorbers, the Y$_{2}$Fe$_{17}$N$_{3-\delta }$ particles were coated with silica (Y$_{2}$Fe$_{17}$N$_{3-\delta }$@SiO$_{2}$) and absorbers with different volume fractions were prepared. The relationship between impedance matching, matching thickness, and the strongest reflection loss peak (${\rm RL}_{\rm min}$) was presented obviously. Compared to the microwave absorption properties of Y$_{2}$Fe$_{17}$N$_{3-\delta }$/PU absorber, Y$_{2}$Fe$_{17}$N$_{3-\delta }$@SiO$_{2}$/PU absorbers are more conducive to the realization of microwave absorption material standards which are thin thickness, light weight, strong absorbing intensity, and broad bandwidth. Based on microwave frequency bands, the microwave absorption properties of the absorbers were analyzed and the related parameters were listed. As an important parameter related to perfect matching, reflection factor ($\sqrt {ărepsilon_{\rm r}/\mu_{\rm r}}$) was discussed combined with microwave amplitude attenuation. According to the origin and mathematical model of bandwidth, the formula of EAB (${\rm RL}<-10$ dB) was derived and simplified. The calculated bandwidths agreed well with experimental results.

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Structure of continuous matrix product operator for transverse field Ising model: An analytic and numerical study Yueshui Zhang(张越水) and Lei Wang(王磊) Chin. Phys. B, 2022, 31 (11): 110205.   DOI: 10.1088/1674-1056/ac8a8f Abstract （125）   HTML （4）    PDF （1049KB）（77）       Knowledge map    We study the structure of the continuous matrix product operator (cMPO)[1] for the transverse field Ising model (TFIM). We prove TFIM's cMPO is solvable and has the form $T=\rm{e}^{-\frac{1}{2}\hat{H}_{\rm F}}$. $\hat{H}_{\rm F}$ is a non-local free fermionic Hamiltonian on a ring with circumference $\beta$, whose ground state is gapped and non-degenerate even at the critical point. The full spectrum of $\hat{H}_{\rm F}$ is determined analytically. At the critical point, our results verify the state-operator-correspondence[2] in the conformal field theory (CFT). We also design a numerical algorithm based on Bloch state ansatz to calculate the low-lying excited states of general (Hermitian) cMPO. Our numerical calculations coincide with the analytic results of TFIM. In the end, we give a short discussion about the entanglement entropy of cMPO's ground state.

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Switching plasticity in compensated ferrimagnetic multilayers for neuromorphic computing Weihao Li(李伟浩), Xiukai Lan(兰修凯), Xionghua Liu(刘雄华), Enze Zhang(张恩泽), Yongcheng Deng(邓永城), and Kaiyou Wang(王开友) Chin. Phys. B, 2022, 31 (11): 117106.   DOI: 10.1088/1674-1056/ac89dd Abstract （133）   HTML （4）    PDF （2967KB）（106）       Knowledge map    Current-induced multilevel magnetization switching in ferrimagnetic spintronic devices is highly pursued for the application in neuromorphic computing. In this work, we demonstrate the switching plasticity in Co/Gd ferrimagnetic multilayers where the binary states magnetization switching induced by spin-orbit toque can be tuned into a multistate one as decreasing the domain nucleation barrier. Therefore, the switching plasticity can be tuned by the perpendicular magnetic anisotropy of the multilayers and the in-plane magnetic field. Moreover, we used the switching plasticity of Co/Gd multilayers for demonstrating spike timing-dependent plasticity and sigmoid-like activation behavior. This work gives useful guidance to design multilevel spintronic devices which could be applied in high-performance neuromorphic computing.

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Interface engineering of transition metal dichalcogenide/GaN heterostructures: Modified broadband for photoelectronic performance Yinlu Gao(高寅露), Kai Cheng(程开), Xue Jiang(蒋雪), and Jijun Zhao(赵纪军) Chin. Phys. B, 2022, 31 (11): 117304.   DOI: 10.1088/1674-1056/ac6eee Abstract （77）   HTML （3）    PDF （3878KB）（46）       Knowledge map    The GaN-based heterostructures are widely used in optoelectronic devices, but the complex surface reconstructions and lattice mismatch greatly limit the applications. The stacking of two-dimensional transition metal dichalcogenide (TMD = MoS2, MoSSe and MoSe2) monolayers on reconstructed GaN surface not only effectively overcomes the larger mismatch, but also brings about novel electronic and optical properties. By adopting the reconstructed GaN (0001) surface with adatoms (N-ter GaN and Ga-ter GaN), the influences of complicated surface conditions on the electronic properties of heterostructures have been investigated. The passivated N-ter and Ga-ter GaN surfaces push the mid-gap states to the valence bands, giving rise to small bandgaps in heterostructures. The charge transfer between Ga-ter GaN surface and TMD monolayers occurs much easier than that across the TMD/N-ter GaN interfaces, which induces stronger interfacial interaction and larger valence band offset (VBO). The band alignment can be switched between type-I and type-II by assembling different TMD monolayers, that is, MoS2/N-ter GaN and MoS2/Ga-ter GaN are type-II, and the others are type-I. The absorption of visible light is enhanced in all considered TMD/reconstructed GaN heterostructures. Additionally, MoSe2/Ga-ter GaN and MoSSe/N-ter GaN have larger conductor band offset (CBO) of 1.32 eV and 1.29 eV, respectively, extending the range from deep ultraviolet to infrared regime. Our results revel that the TMD/reconstructed GaN heterostructures may be used for high-performance broadband photoelectronic devices.

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Experimental demonstration of a fast calibration method for integrated photonic circuits with cascaded phase shifters Junqin Cao(曹君勤), Zhixin Chen(陈志歆), Yaxin Wang(王亚新), Tianfeng Feng(冯田峰), Zhihao Li(李志浩), Zeyu Xing(邢泽宇), Huashan Li(李华山), and Xiaoqi Zhou(周晓祺) Chin. Phys. B, 2022, 31 (11): 114204.   DOI: 10.1088/1674-1056/ac8737 Abstract （75）   HTML （3）    PDF （1208KB）（42）       Knowledge map    With the development of research on integrated photonic quantum information processing, the integration level of the integrated quantum photonic circuits has been increasing continuously, which makes the calibration of the phase shifters on the chip increasingly difficult. For the calibration of multiple cascaded phase shifters that is not easy to be decoupled, the resources consumed by conventional brute force methods increase exponentially with the number of phase shifters, making it impossible to calibrate a relatively large number of cascaded phase shifters. In this work, we experimentally validate an efficient method for calibrating cascaded phase shifters that achieves an exponential increase in calibration efficiency compared to the conventional method, thus solving the calibration problem for multiple cascaded phase shifters. Specifically, we experimentally calibrate an integrated quantum photonic circuit with nine cascaded phase shifters and achieve a high-precision calibration with an average fidelity of 99.26%.

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Optical study on topological superconductor candidate Sr-doped Bi2Se3 Jialun Liu(刘佳伦), Chennan Wang(王晨南), Tong Lin(林桐), Liye Cao(曹立叶), Lei Wang(王蕾), Jiaji Li(李佳吉), Zhen Tao(陶镇), Nan Shen(申娜), Rina Wu(乌日娜), Aifang Fang(房爱芳), Nanlin Wang(王楠林), and Rongyan Chen(陈荣艳) Chin. Phys. B, 2022, 31 (11): 117402.   DOI: 10.1088/1674-1056/ac7a10 Abstract （61）   HTML （0）    PDF （850KB）（28）       Knowledge map    Utilizing infrared spectroscopy, we study the charge dynamics of the topological superconductor candidate Sr$_x$Bi$_2$Se$_3$. The frequency-dependent reflectivity $R(\omega$) demonstrates metallic feature and the scattering rate of the free carriers decreases with temperature decreasing. The plasma edge shows a slight blue shift upon cooling, similar to the behavior of Cu$_x$Bi$_2$Se$_3$. As the carrier concentration $n$ obtained by Hall resistivity increases slightly with the decreasing temperature, the effective mass is proved to increase as well, which is in contrast with that of Cu$_x$Bi$_2$Se$_3$.We also perform the ultrafast pump-probe study on the Sr$_{0.2}$Bi$_2$Se$_3$ compounds. Resembling its parent compound Bi$_2$Se$_3$, three distinct relaxation processes are found to contribute to the transient reflectivity. However, the deduced relaxation times are quite different. In addition, the electron-optical-phonon coupling constant is identified to be $\lambda = 0.88$.

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Experimental realization of two-dimensional single-layer ultracold gases of 87Rb in an accordion lattice Liangwei Wang(王良伟), Kai Wen(文凯), Fangde Liu(刘方德), Yunda Li(李云达), Pengjun Wang(王鹏军), Lianghui Huang(黄良辉), Liangchao Chen(陈良超), Wei Han(韩伟), Zengming Meng(孟增明), and Jing Zhang(张靖) Chin. Phys. B, 2022, 31 (10): 103401.   DOI: 10.1088/1674-1056/ac873c Abstract （252）   HTML （17）    PDF （1293KB）（210）       Knowledge map    We experimentally realize two-dimensional (2D) single-layer ultracold gases of 87Rb by dynamically tuning the periodicity of a standing wave, known as accordion lattice. In order to load 87Rb Bose—Einstein condensate into single dark fringe node of the blue detuning optical lattice, we reduce the lattice periodicity from 26.7 μ to 3.5 μ with the help of an acousto-optic deflector (AOD) to compress the three-dimensional BEC adiabatically into a flat and uniform quasi-2D single-layer. We describe the experimental procedure of the atoms loading into the accordion lattice in detail and present the characteristics of the quasi-2D ultracold gases. This setup provides an important platform for studying in- and out-of equilibrium physics, phase transition and 2D topological matter.

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Boosting the performance of crossed ZnO microwire UV photodetector by mechanical contact homo-interface barrier Yinzhe Liu(刘寅哲), Kewei Liu(刘可为), Jialin Yang(杨佳霖), Zhen Cheng(程祯), Dongyang Han(韩冬阳), Qiu Ai(艾秋), Xing Chen(陈星), Yongxue Zhu(朱勇学), Binghui Li(李炳辉), Lei Liu(刘雷), and Dezhen Shen(申德振) Chin. Phys. B, 2022, 31 (10): 106101.   DOI: 10.1088/1674-1056/ac80b0 Abstract （144）   HTML （9）    PDF （1039KB）（112）       Knowledge map    One-dimensional (1D) micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors. However, in the axial direction of micro/nanowires, the carriers can transport freely driven by an external electric field, which usually produces large dark current and low detectivity. Here, an UV photodetector built from three cross-intersecting ZnO microwires with double homo-interfaces is demonstrated by the chemical vapor deposition and physical transfer techniques. Compared with the reference device without interface, the dark current of this ZnO double-interface photodetector is significantly reduced by nearly 5 orders of magnitude, while the responsivity decreases slightly, thereby greatly improving the normalized photocurrent-to-dark current ratio. In addition, ZnO double-interface photodetector exhibits a much faster response speed (～ 0.65 s) than the no-interface device (～ 95 s). The improved performance is attributed to the potential barriers at the microwire—microwire homo-interfaces, which can regulate the carrier transport. Our findings in this work provide a promising approach for the design and development of high-performance photodetectors.

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Identification of the phosphorus-doping defect in MgS as a potential qubit Jijun Huang(黄及军) and Xueling Lei(雷雪玲) Chin. Phys. B, 2022, 31 (10): 106102.   DOI: 10.1088/1674-1056/ac7dbc Abstract （102）   HTML （4）    PDF （1973KB）（66）       Knowledge map    The PS defect is obtained by replacing one S atom with one P atom in the wide-bandgap semiconductor MgS. Based on first-principles calculations, the formation energy, defect levels, and electronic structure of the PS defect in different charge states are evaluated. We predict that the neutral PS0 and positively charged PS+1 are the plausible qubit candidates for the construction of quantum systems, since they maintain the spin conservation during optical excited transition. The zero-phonon lines at the PS0 and PS+1 defects are 0.43 eV and 0.21 eV, respectively, which fall in the infrared band. In addition, the zero-field splitting parameter D of the PS+1 with spin-triplet is 2920 MHz, which is in the range of microwave, showing that the PS+1 defect can be manipulated by microwave. Finally, the principal values of the hyperfine tensor are examined, it is found that they decay exponentially with the distance from the defect site.

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Unusual thermodynamics of low-energy phonons in the Dirac semimetal Cd3As2 Zhen Wang(王振), Hengcan Zhao(赵恒灿), Meng Lyu(吕孟), Junsen Xiang(项俊森), Qingxin Dong(董庆新), Genfu Chen(陈根富), Shuai Zhang(张帅), and Peijie Sun(孙培杰) Chin. Phys. B, 2022, 31 (10): 106501.   DOI: 10.1088/1674-1056/ac8928 Abstract （88）   HTML （5）    PDF （693KB）（56）       Knowledge map    By studying the thermal conductivity, specific heat, elastic modulus, and thermal expansion as a function of temperature for Cd3As2, we have unveiled a couple of important thermodynamic features of the low-energy phonons strongly interacting with Dirac electrons. The existence of soft optical phonons, as inferred from the extremely low thermal conductivity, is unambiguously confirmed by low-temperature specific heat revealing significant deviation from Debye's description. The estimated Debye temperature is small in the range of 100—200 K and varies significantly depending upon the measurement used in its experimental determination. The thermodynamic Grüneisen ratio γ reveals a remarkable reduction below about 100 K, an energy scale that is highly relevant to the Dirac states, towards negative values below about 10 K that are indicative of lattice instability.

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Ac Josephson effect in Corbino-geometry Josephson junctions constructed on Bi2Te3 surface Yunxiao Zhang(张云潇), Zhaozheng Lyu(吕昭征), Xiang Wang(王翔), Enna Zhuo(卓恩娜), Xiaopei Sun(孙晓培), Bing Li(李冰), Jie Shen(沈洁), Guangtong Liu(刘广同), Fanming Qu(屈凡明), and Li Lü(吕力) Chin. Phys. B, 2022, 31 (10): 107402.   DOI: 10.1088/1674-1056/ac89d4 Abstract （79）   HTML （5）    PDF （1805KB）（68）       Knowledge map    Recently, a Corbino-geometry type of Josephson junction constructed on the surface of topological insulators has been proposed for hosting and braiding Majorana zero modes. As a first step to test this proposal, we successfully fabricated Corbino-geometry Josephson junctions (JJs) on the surface of Bi2Te3 flakes. Ac Josephson effect with fractional Shapiro steps was observed in the Corbino-geometry JJs while the flux in the junction area was quantized. By analyzing the experimental data using the resistively shunted Josephson junction model, we found that the Corbino-geometry JJs exhibit a skewed current—phase relation due to its high transparency. The results suggest that Corbino-geometry JJs constructed on the surface of topological insulators may provide a promising platform for studying Majorana-related physics.

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Peptide backbone-copper ring structure: A molecular insight into copper-induced amyloid toxicity Jing Wang(王静), Hua Li(李华), Xiankai Jiang(姜先凯), Bin Wu(吴斌), Jun Guo(郭俊), Xiurong Su(苏秀榕), Xingfei Zhou(周星飞), Yu Wang(王宇), Geng Wang(王耿), Heping Geng(耿和平), Zheng Jiang(姜政), Fang Huang(黄方), Gang Chen(陈刚), Chunlei Wang(王春雷), Haiping Fang(方海平), and Chenqi Xu(许琛琦) Chin. Phys. B, 2022, 31 (10): 108702.   DOI: 10.1088/1674-1056/ac8920 Abstract （103）   HTML （1）    PDF （3845KB）（53）       Knowledge map    Copper ions can promote amyloid diseases that are associated with amyloid peptides, such as type 2 diabetes (T2D), Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). However, the underlying molecular mechanism remains obscure. Here we present that Cu2+ is able to specifically bind to the backbone of T2D-related human islet amyloid polypeptide (hIAPP) by forming a ring structure, which causes the reduction of Cu2+ to Cu+ to produce reactive oxygen species (ROS) and the modulation of hIAPP aggregation. Nuclear magnetic resonance spectroscopy showed that Cu2+ bound to the backbone of a turn region, His18—Ser21, which is critical for hIAPP aggregation. Ab initio calculations and x-ray absorption fine structure analyses revealed that Cu2+ simultaneously bound with both the amide nitrogen and carbonyl oxygen on the peptide backbone, resulting in a ring structure, and causing the reduction of Cu2+ to Cu+ to form a hIAPP-Cu+ complex. 2',7'-dichlorodihydrofluorescin diacetate fluorescence measurements further indicated that this complex led to enhanced ROS levels in rat insulinoma cells. Additionally, thioflavin T fluorescence and atomic force microscopy measurements denoted that the backbone-Cu ring structure largely modulated hIAPP aggregation, including the inhibition of hIAPP fibrillation and the promotion of peptide oligomerization. These findings shed new light on the molecular mechanism of Cu2+-induced amyloid toxicity involving both the enhancement of ROS and the modulation of hIAPP aggregation.

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Slight Co-doping tuned magnetic and electric properties on cubic BaFeO3 single crystal Shijun Qin(覃湜俊), Bowen Zhou(周博文), Zhehong Liu(刘哲宏), Xubin Ye(叶旭斌), Xueqiang Zhang(张雪强), Zhao Pan(潘昭), and Youwen Long(龙有文) Chin. Phys. B, 2022, 31 (9): 097503.   DOI: 10.1088/1674-1056/ac7549 Abstract （289）   HTML （19）    PDF （2095KB）（251）       Knowledge map    The single crystal of cubic perovskite BaFeO$_{3}$ shows multiple magnetic transitions and external stimulus sensitive magnetism. In this paper, a 5%-Co-doped BaFeO$_{3}$ (i.e. BaFe$_{0.95}$Co$_{0.05}$O$_{3})$ single crystal was grown by combining floating zone methods with high-pressure techniques. Such a slight Co doping has little effect on crystal structure, but significantly changes the magnetism from the parent antiferromagnetic ground state to a ferromagnetic one with the Curie temperature $T_{\rm C} \approx 120$ K. Compared with the parent BaFeO$_{3}$ at the induced ferromagnetic state, the saturated magnetic moment of the doped BaFe$_{0.95}$Co$_{0.05}$O$_{3}$ increases by about 10% and reaches 3.64 $\mu_{\rm B}$/f.u. Resistivity and specific heat measurements show that the ferromagnetic ordering favors metallic-like electrical transport behavior for BaFe$_{0.95}$Co$_{0.05}$O$_{3}$. The present work indicates that Co-doping is an effective method to tune the magnetic and electric properties for the cubic perovskite phase of BaFeO$_{3}$.

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Josephson vortices and intrinsic Josephson junctions in the layered iron-based superconductor Ca10(Pt3As8)((Fe0.9Pt0.1)2As2)5 Qiang-Tao Sui(随强涛) and Xiang-Gang Qui(邱祥冈) Chin. Phys. B, 2022, 31 (9): 097403.   DOI: 10.1088/1674-1056/ac76ae Abstract （134）   HTML （7）    PDF （1517KB）（100）       Knowledge map    Modulated electronic state due to the layered crystal structures brings about moderate anisotropy of superconductivity in the iron-based superconductors and thus Abrikosov vortices are expected in the mixed state. However, based on the angular and temperature dependent transport measurements in iron-based superconductor Ca$_{10}$(Pt$_3$As$_8$)((Fe$_{0.9}$Pt$_{0.1}$)$_2$As$_2$)$_5$ with $T_{\rm c} \simeq 12$ K, we find clear evidences of a crossover from Abrikosov vortices to Josephson vortices at a crossover temperature $T^{\star} \simeq 7 $ K, when the applied magnetic field is parallel to the superconducting FeAs layers, i.e., the angle between the magnetic field and the FeAs layers $\theta = 0^\circ$. This crossover to Josephson vortices is demonstrated by an abnormal decrease (increase) of the critical current (flux-flow resistance) below $T^{\star}$, in contrast to the increase (decrease) of the critical current (flux-flow resistance) above $T^{\star}$ expected for Abrikosov vortices. Furthermore, when $\theta$ is larger than $0.5^\circ$, the flux-flow resistance and critical current have no anomalous behaviors across $T^{\star}$. These anomalous behaviors can be understood in terms of the distinct transition from the well-pinned Abrikosov vortices to the weakly-pinned Josephson vortices upon cooling, when the coherent length perpendicular to the FeAs layers $\xi_\bot$ becomes shorter than half of the interlayer distance $d/2$. These experimental findings indicate the existence of intrinsic Josephson junctions below $T^{\star}$ and thus quasi-two-dimensional superconductivity in Ca$_{10}$(Pt$_3$As$_8$)((Fe$_{0.9}$Pt$_{0.1}$)$_2$As$_2$)$_5$, similar to those in the cuprate superconductors.

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Finite superconducting square wire-network based on two-dimensional crystalline Mo2C Zhen Liu(刘震), Zi-Xuan Yang(杨子萱), Chuan Xu(徐川), Jia-Ji Zhao(赵嘉佶), Lu-Junyu Wang(王陆君瑜), Yun-Qi Fu(富云齐), Xue-Lei Liang(梁学磊), Hui-Ming Cheng(成会明), Wen-Cai Ren(任文才), Xiao-Song Wu(吴孝松), and Ning Kang(康宁) Chin. Phys. B, 2022, 31 (9): 097404.   DOI: 10.1088/1674-1056/ac67c7 Abstract （110）   HTML （5）    PDF （2372KB）（83）       Knowledge map    Superconducting wire-networks are paradigms to study Cooper pairing issues, vortex dynamics and arrangements. Recently, emergent low-dimensional crystalline superconductors were reported in the minimal-disorder limit, providing novel platforms to reveal vortices-related physics. Study on superconducting loops with high-crystallinity is thus currently demanded. Here, we report fabrication and transport measurement of finite square-network based on two-dimensional crystalline superconductor Mo2C. We observe oscillations in the resistance as a function of the magnetic flux through the loops. Resistance dips at both matching field and fractional fillings are revealed. Temperature and current evolutions are carried out in magnetoresistance to study vortex dynamics. The amplitude of oscillation is enhanced due to the interaction between thermally activated vortices and the currents induced in the loops. The driving current reduces the effective activation energy for vortex, giving rise to stronger vortex interaction. Moreover, by the thermally activated vortex creep model, we derive the effective potential barrier for vortex dissipation, which shows well-defined correspondence with structures in magnetoresistance. Our work shows that low-dimensional crystalline superconducting network based on Mo2C possesses pronounced potential in studying the modulation of vortex arrangements and dynamics, paving the way for further investigations on crystalline superconducting network with various configurations.

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Liquid-phase synthesis of Li2S and Li3PS4 with lithium-based organic solutions Jieru Xu(许洁茹), Qiuchen Wang(王秋辰), Wenlin Yan(闫汶琳), Liquan Chen(陈立泉), Hong Li(李泓), and Fan Wu(吴凡) Chin. Phys. B, 2022, 31 (9): 098203.   DOI: 10.1088/1674-1056/ac7459 Abstract （95）   HTML （3）    PDF （7428KB）（53）       Knowledge map    Sulfide solid electrolytes are widely regarded as one of the most promising technical routes to realize all-solid-state batteries (ASSBs) due to their high ionic conductivity and favorable deformability. However, the relatively high price of the crucial starting material, Li2S, results in high costs of sulfide solid electrolytes, limiting their practical application in ASSBs. To solve this problem, we develop a new synthesis route of Li2S via liquid-phase synthesis method, employing lithium and biphenyl in 1, 2-dimethoxyethane (DME) ether solvent to form a lithium solution as the lithium precursor. Because of the comparatively strong reducibility of the lithium solution, its reaction with sulfur proceeds effectively even at room temperature. This new synthesis route of Li2S starts with cheap precursors of lithium, sulfur, biphenyl and DME solvent, and the only remaining byproduct (DME solution of biphenyl) after the collection of Li2S product can be recycled and reused. Besides, the reaction can proceed effectively at room temperature with mild condition, reducing energy cost to a great extent. The as-synthesized Li2S owns uniform and extremely small particle size, proved to be feasible in synthesizing sulfide solid electrolytes (such as the solid-state synthesis of Li6PS5Cl). Spontaneously, this lithium solution can be directly employed in the synthesis of Li3PS4 solid electrolytes via liquid-phase synthesis method, in which the centrifugation and heat treatment processes of Li2S are not necessary, providing simplified production process. The as-synthesized Li3PS4 exhibits typical Li+ conductivity of 1.85×10-4 S·cm-1 at 30 ℃.

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On the Onsager-Casimir reciprocal relations in a tilted Weyl semimetal Bingyan Jiang(江丙炎), Jiaji Zhao(赵嘉佶), Lujunyu Wang(王陆君瑜), Ran Bi(毕然), Juewen Fan(范珏雯), Zhilin Li(李治林), and Xiaosong Wu(吴孝松) Chin. Phys. B, 2022, 31 (9): 097306.   DOI: 10.1088/1674-1056/ac754a Abstract （96）   HTML （5）    PDF （2042KB）（61）       Knowledge map    The Onsager-Casimir reciprocal relations are a fundamental symmetry of nonequilibrium statistical systems. Here we study an unusual chirality-dependent Hall effect in a tilted Weyl semimetal Co3Sn2S2 with broken time-reversal symmetry. It is confirmed that the reciprocal relations are satisfied. Since two Berry curvature effects, an anomalous velocity and a chiral chemical potential, contribute to the observed Hall effect, the reciprocal relations suggest their intriguing connection.

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Enhancement of spin-orbit torque efficiency by tailoring interfacial spin-orbit coupling in Pt-based magnetic multilayers Wenqiang Wang(王文强), Gengkuan Zhu(朱耿宽), Kaiyuan Zhou(周恺元), Xiang Zhan(战翔), Zui Tao(陶醉), Qingwei Fu(付清为), Like Liang(梁力克), Zishuang Li(李子爽), Lina Chen(陈丽娜), Chunjie Yan(晏春杰), Haotian Li(李浩天), Tiejun Zhou(周铁军), and Ronghua Liu(刘荣华) Chin. Phys. B, 2022, 31 (9): 097504.   DOI: 10.1088/1674-1056/ac76aa Abstract （111）   HTML （6）    PDF （1342KB）（73）       Knowledge map    We study inserting Co layer thickness-dependent spin transport and spin-orbit torques (SOTs) in the Pt/Co/Py trilayers by spin-torque ferromagnetic resonance. The interfacial perpendicular magnetic anisotropy (IPMA) energy density ($K_{\rm s}= 2.7 $ erg/cm$^{2}$, 1 erg = 10$^{-7}$ J), which is dominated by interfacial spin-orbit coupling (ISOC) in the Pt/Co interface, total effective spin-mixing conductance $(G_{\mathrm{eff,tot}}^{\mathrm{\uparrow \downarrow }}=\mathrm{0.42\times }{10}^{15} \mathrm{\Omega }^{-1}\cdot\mathrm{m}^{-2}$) and two-magnon scattering ($\beta_{\mathrm{TMS}}= 0.46 {\mathrm{nm}}^{2}$) are first characterized, and the damping-like torque ($\xi_{\mathrm{DL}}= 0.103$) and field-like torque ($\xi _{\mathrm{FL}}=-0.017$) efficiencies are also calculated quantitatively by varying the thickness of the inserting Co layer. The significant enhancement of $\xi_{\mathrm{DL}}$ and $\xi_{\mathrm{FL}}$ in Pt/Co/Py than Pt/Py bilayer system originates from the interfacial Rashba-Edelstein effect due to the strong ISOC between Co-3d and Pt-5d orbitals at the Pt/Co interface. Additionally, we find a considerable out-of-plane spin polarization SOT, which is ascribed to the spin anomalous Hall effect and possible spin precession effect due to IPMA-induced perpendicular magnetization at the Pt/Co interface. Our results demonstrate that the ISOC of the Pt/Co interface plays a vital role in spin transport and SOTs-generation. Our finds offer an alternative approach to improve the conventional SOTs efficiencies and generate unconventional SOTs with out-of-plane spin polarization to develop low power Pt-based spintronic via tailoring the Pt/FM interface.

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Bioinspired tactile perception platform with information encryption function Zhi-Wen Shi(石智文), Zheng-Yu Ren(任征宇), Wei-Sheng Wang(王伟胜), Hui Xiao(肖惠), Yu-Heng Zeng(曾俞衡), and Li-Qiang Zhu(竺立强) Chin. Phys. B, 2022, 31 (9): 098506.   DOI: 10.1088/1674-1056/ac7a15 Abstract （205）   HTML （6）    PDF （3270KB）（87）       Knowledge map    Mimicking tactile perception is critical to the development of advanced interactive neuromorphic platforms. Inspired by cutaneous perceptual functions, a bionic tactile perceptual platform is proposed. PDMS-based tactile sensors act as bionic skin touch receptors. Flexible indium tin oxide neuromorphic transistors fabricated with a single-step mask processing act as artificial synapses. Thus, the tactile perceptual platform possesses the ability of information processing. Interestingly, the flexible tactile perception platform can find applications in information encryption and decryption. With adoption of cipher, signal transmitted by the perception platform is encrypted. Thus, the security of information transmission is effectively improved. The flexible tactile perceptual platform would have potentials in cognitive wearable devices, advanced human-machine interaction system, and intelligent bionic robots.

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Monolayer MoS2 of high mobility grown on SiO2 substrate by two-step chemical vapor deposition Jia-Jun Ma(马佳俊), Kang Wu(吴康), Zhen-Yu Wang(王振宇), Rui-Song Ma(马瑞松), Li-Hong Bao(鲍丽宏), Qing Dai(戴庆), Jin-Dong Ren(任金东), and Hong-Jun Gao(高鸿钧) Chin. Phys. B, 2022, 31 (8): 088105.   DOI: 10.1088/1674-1056/ac6737 Abstract （352）   HTML （17）    PDF （1277KB）（310）       Knowledge map    We report a novel two-step ambient pressure chemical vapor deposition (CVD) pathway to grow high-quality MoS2 monolayer on the SiO2 substrate with large crystal size up to 110 μm. The large specific surface area of the pre-synthesized MoO3 flakes on the mica substrate compared to MoO3 powder could dramatically reduce the consumption of the Mo source. The electronic information inferred from the four-probe scanning tunneling microscope (4P-STM) image explains the threshold voltage variations and the n-type behavior observed in the two-terminal transport measurements. Furthermore, the direct van der Pauw transport also confirms its relatively high carrier mobility. Our study provides a reliable method to synthesize high-quality MoS2 monolayer, which is confirmed by the direct 4P-STM measurement results. Such methodology is a key step toward the large-scale growth of transition metal dichalcogenides (TMDs) on the SiO2 substrate and is essential to further development of the TMDs-related integrated devices.

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