Half-quantized helical hinge currents in axion insulators  

作　　者：Ming Gong Haiwen Liu Hua Jiang Chui-Zhen Chen X-C.Xie 

机构地区：[1]International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China [2]Center for Advanced Quantum Studies,Department of Physics,Beijing Normal University,Beijing 100875,China [3]School of Physical Science and Technology,Soochow University,Suzhou 215006,China [4]Institute for Advanced Study,Soochow University,Suzhou 215006,China [5]CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China

出　　处：《National Science Review》2023年第9期148-156,共9页国家科学评论（英文版）

基　　金：This work was financially supported by the National Key R&D Program of China(2022YFA1403700,2019YFA0308403 and 2015CB921102);the National Natural Science Foundation of China(11974256);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB28000000).

摘　　要：Fractional quantization can emerge in noncorrelated systems due to the parity anomaly,while its condensed matter realization is a challenging problem.We propose that in axion insulators(AIs),parity anomaly manifests a unique fractional boundary excitation:the half-quantized helical hinge currents.These helical hinge currents microscopically originate from the lateral Goos-Hanchen(GH)shift of massless side-surface Dirac electrons that are totally reflected from the hinges.Meanwhile,due to the presence of the massive top and bottom surfaces of the AI,the helical current induced by the GHshift is half-quantized.The semiclassical wave packet analysis uncovers that the hinge current has a topological origin and its half quantization is robust to parameter variations.Lastly,we propose an experimentally feasible six-terminal device to identify the half-quantized hinge channels by measuring the nonreciprocal conductances.Our results advance the realization of the half-quantization and topological magnetoelectric responses in AIs.

关 键 词：axion insulator parity anomaly half-quantization Goos-Hanchen effect topological magnetoelectric effect 

分 类 号：O469[理学—凝聚态物理]