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Nonlinear Seebeck and Peltier effects in a Majorana nanowire coupled to leads

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Chinese Physics B 2024年第7期33卷 547-552页

作者：迟锋刘佳付振国刘黎明易子川 School of Electronic and Information Engineering UESTC of ChinaZhongshan InstituteZhongshan 528400China School of Science Inner Mongolia University of Science and TechnologyBaotou 014010China institute of applied Physics and computational mathematics Beijing 100088China

We theoretically study nonlinear thermoelectric transport through a topological superconductor nanowire hosting Majorana bound states(MBSs) at its two ends, a system named as Majorana nanowire(MNW). We consider that the MNW is coupled to the left and right normal metallic leads subjected to either bias voltage or temperature gradient. We focus our attention on the sign change of nonlinear Seebeck and Peltier coefficients induced by mechanisms related to the MBSs, by which the possible existence of MBSs might be proved. Our results show that for a fixed temperature difference between the two leads, the sign of the nonlinear Seebeck coefficient(thermopower) can be reversed by changing the overlap amplitude between the MBSs or the system equilibrium temperature, which are similar to the cases in linear response regime. By optimizing the MBS–MBS interaction amplitude and system equilibrium temperature, we find that the temperature difference may also induce sign change of the nonlinear thermopower. For zero temperature difference and finite bias voltage, both the sign and magnitude of nonlinear Peltier coefficient can be adjusted by changing the bias voltage or overlap amplitude between the MBSs. In the presence of both bias voltage and temperature difference, we show that the electrical current at zero Fermi level and the states induced by overlap between the MBSs keep unchanged, regardless of the amplitude of temperature difference. We also find that the direction of the heat current driven by bias voltage may be changed by weak temperature difference.

关键词： quantum dot nonlinear Seebeck coefficient Peltier coefficient Majorana bound states sign change

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A deep learning interatomic potential suitable for simulating radiation damage in bulk tungsten

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Tungsten 2024年第2期6卷 304-322页

作者： Chang-Jie Ding Ya-Wei Lei Xiao-Yang Wang Xiao-Lin Li Xiang-Yan Li Yan-Ge Zhang Yi-Chun Xu Chang-Song Liu Xue-Bang Wu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island University of Science and Technology of ChinaHefei 230026China Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.

关键词： Machine learning Deep learning Interatomic potential Radiation damage Tungsten

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Self-consistent and precise measurement of time-dependent radiative albedo of gold based on specially symmetrical triple-cavity Hohlraum

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Matter and Radiation at Extremes 2024年第3期9卷 57-64页

作者： Zhiyu Zhang Yang Zhao Xiaoying Han Liling Li Bo Qing Lifei Hou Yulong Li YuXue Zhang Huan Zhang Xiangming Liu Bo Deng Gang Xiong Min Lv Tuo Zhu Chengwu Huang Tianming Song Yan Zhao Yingjie Li Lu Zhang Xufei Xie Jiyan Zhang Jiamin Yang Laser Fusion Research Center China Academy of Engineering PhysicsMianyang 621900China National Key Laboratory of Plasma Physcis Mianyang 621900China institute of applied Physics and computational mathematics Beijing 100088China

A self-consistent and precise method to determine the time-dependent radiative albedo,i.e.,the ratio of the reemission flux to the incident flux,for an indirect-drive inertial confinement fusion Hohlraum wall material is proposed.A specially designed symmetrical triple-cavity gold Hohlraum is used to create approximately constant and near-equilibrium uniform radiation with a peak temperature of 160 *** incident flux at the secondary cavity waist is obtained from flux balance analysis and from the shock velocity of a standard *** results agree well owing to the symmetrical radiation in the secondary cavity.A self-consistent and precise time-dependent radiative albedo is deduced from the reliable reemission flux and the incident flux,and the result from the shock velocity is found to have a smaller uncertainty than that from the multi-angle flux balance analysis,and also to agree well with the result of a simulation using the HYADES opacity.

关键词： precise cavity radiative

Sharp well-posedness for higher-order Schr?dinger equations on torus and sphere

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Acta Mathematica Sinica,English Series 2024年

作者： Sijie QIAN Jiqiang ZHENG The Graduate School of China Academy of Engineering Physics institute of applied Physics and computational mathematics Beijing National Key Laboratory of computational Physics

In this paper,we establish the sharp local uniform well-posedness of the higher-order nonlinear Schr?dinger equations （HNLS） with cubic nonlinear terms i?2_tu+（-?g）mu=-|u|2u on *** bilinear estimates and lattice point estimates,we prove that the well-posedness thresholds are s2c（T,m）=0 and sc（2S,m）=1/4 for any order m∈*** contrast,for Euclidean spaces,it has been shown in[*** and ***,Discrete and Continuous Dynamical Systems,17（2006）,181-200.]that sc（dR,m）=d/2-m if m更多还原AbstractFilter('ChDivSummary', 'ChDivSummaryMore', 'ChDivSummaryReset');

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Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

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Nano Research 2024年第4期17卷 2712-2718页

作者： Yufeng Luo Zhenhan Fang Zixin Hong Shaorong Duan Haitao Liu Hengcai Wu Qunqing Li Yuegang Zhang Shoushan Fan Wenhui Duan Jiaping Wang Tsinghua-Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Frontier Science Center for Quantum Information Tsinghua UniversityBeijing 100084China

Polar promotors have been proven effective in catalyzing the polysulfide(PS)reduction reaction(PSRR)process in lithium-sulfur(Li-S)***,the promotor surface tends to be poisoned due to the accumulation of insoluble discharging products of lithium disulfide(Li_(2)S_(2))and lithium sulfide(Li_(2)S)during Li-S battery ***,we investigate the detailed PSRR mechanism on the surface of manganese sulfides(MnS)as a representative promoter by performing in-situ Raman mapping *** catalytic ability of MnS enables thorough electrochemical reduction of PSs to Li_(2)S_(2) and Li_(2)S on the MnS *** generated Li_(2)S_(2) and Li_(2)S then adsorb the dissolved PSs via chemical reactions among sulfur species during the subsequent PSRR *** phenomenon mitigates promotor poisoning and continuously improves the reversible ***,the assembled Li-S cell demonstrates excellent electrochemical performance after introducing a conductive interlayer containing a thin piece of carbon nanotube film and MnS promotors.

关键词： promotors polysulfides chemical reactions catalytic ability in-situ Raman measurements

A CELL-CENTERED GODUNOV METHOD BASED ON STAGGERED DATA DISTRIBUTION,PART Ⅰ:ONE-DIMENSIONAL CASE

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Journal of computational mathematics 2024年第4期42卷 1172-1196页

作者： Jiayin Zhai Xiao Li Zhijun Shen institute of applied Physics and computational mathematics LCPP.O.Box 8009-26Beijing 100088China College of Big Data and Internet Shenzhen Technology UniversityShenzhen 518118China Center for applied Physics and Technology HEDPSPeking UniversityChina

This paper presents a cell-centered Godunov method based on staggered data distribu-tion in Eulerian *** motivation is to reduce the intrinsic entropy dissipation of classical Godunov methods in the calculation of an isentropic or rarefaction *** the same time,the property of accurate shock capturing is also *** analyzing the factors that cause nonphysical entropy in the conventional Godunov methods,we introduce two velocities rather than a single velocity in a cell to reduce kinetic energy dissipation.A series of redistribution strategies are adopted to update subcell quantities in order to improve *** examples validate that the present method can dramatically reduce nonphysical entropy *** subject classification:35Q35,76N15,76M12.

关键词： Godunov method Riemann solver Rarefaction wave Nonphysical entropy increase.

A FINITE DIFFERENCE METHOD FOR TWO DIMENSIONAL ELLIPTIC INTERFACE PROBLEMS WITH IMPERFECT CONTACT

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Journal of computational mathematics 2024年第5期42卷 1328-1355页

作者： Fujun Cao Dongfang Yuan Dongxu Jia Guangwei Yuan School of Science Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina School of Science Tianjin University of TechnologyTianjin 300384China Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsP.O.Box 8009Beijing 100088China

In this paper two dimensional elliptic interface problem with imperfect contact is considered,which is featured by the implicit jump condition imposed on the imperfect contact interface,and the jumping quantity of the unknown is related to the flux across the interface.A finite difference method is constructed for the 2D elliptic interface problems with straight and curve interface ***,the stability and convergence analysis are given for the constructed ***,in particular case,it is proved to be *** examples for elliptic interface problems with straight and curve interface shapes are tested to verify the performance of the *** numerical results demonstrate that it obtains approximately second-order accuracy for elliptic interface equations with implicit jump condition.

关键词： Finite difference method Elliptic interface problem Imperfect contact

Discovering the ultralow thermal conductive A_(2)B_(2)O_(7)-type high-entropy oxides through the hybrid knowle dge-assiste d data-driven machine learning

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Journal of Materials Science & Technology 2024年第1期168卷 131-142页

作者： Ying Zhang Ke Ren William Yi Wang Xingyu Gao Ruihao Yuan Jun Wang Yiguang Wang Haifeng Song Xiubing Liang Jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Innovation Center NPU ChongqingChongqing 401135China institute of Advanced Structure Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Defense Innovation institute Academy of Military Sciences of the PLA of ChinaBeijing 100071China

Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced *** instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice ***,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced *** the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic ***,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 ***,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκ*** work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.

关键词： High-entropy oxides Thermal conductivity Pyrochlore Key physical parameter First-Principles

Interlayer Magnetic Interaction in the CrI_(3)/CrSe_(2) Heterostructure

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Chinese Physics Letters 2024年第5期41卷 85-89页

作者：王秋皓倪美燕李淑静郑法伟路洪艳张平 School of Physics and physical Engineering Qufu Normal UniversityQufu 273165China Center for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and MeasurementSchool of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China College of mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China institute of applied Physics and computational mathematics Beijing 100088China

Based on first-principles calculations, we systematically study the stacking energy and interlayer magnetic interaction of the heterobilayer composed of CrI_(3) and CrSe_(2) monolayers. It is found that the stacking order plays a crucial role in the interlayer magnetic coupling. Among all possible stacking structures, the AA-stacking is the most stable heterostructure, exhibiting interlayer antiferromagnetic interactions. Interestingly, the interlayer magnetic interaction can be effectively tuned by biaxial strain. A 4.3% compressive strain would result in a ferromagnetic interlayer interaction in all stacking orders. These results reveal the magnetic properties of CrI_(3)/CrSe_(2) heterostructure, which is expected to be applied to spintronic devices.

关键词： strain stacking interlayer

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