非厄米Su-Schrieffer-Heeger链边缘态和趋肤效应依赖的电子输运特性  

Edge states and skin effect dependent electron transport properties of non-Hermitian Su-Schrieffer-Heeger chain

作　　者：杨艳丽 段志磊 薛海斌[2] Yang Yan-Li;Duan Zhi-Lei;Xue Hai-Bin(Teaching Center of Fundamental Courses,Jinzhong College of Information,Jinzhong 030800,China;College of Physics,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]晋中信息学院数理教学部,晋中030800 [2]太原理工大学物理学院,太原030024

出　　处：《物理学报》2023年第24期258-268,共11页Acta Physica Sinica

基　　金：山西省应用基础研究计划(批准号:20210302123184,201601D011015);山西省高等学校优秀青年学术带头人支持计划(批准号:163220120-S);山西省高等学校教学改革创新项目(批准号:J20221492)资助的课题。

摘　　要：在非互易Su-Schrieffer-Heeger(SSH)链中,电子在胞内的跳跃振幅依赖于其跳跃方向,因而,该非厄米SSH链同时存在非平庸拓扑边缘态和非厄米趋肤效应.相应地,如何探测非厄米SSH链的边缘态和趋肤效应成为非厄米物理学的一个重要课题.本文研究了非厄米SSH链的非平庸拓扑边缘态和非厄米趋肤效应对其零能附近电子输运特性的依赖关系.研究发现当电子在零能附近透射率峰的峰值远小于1时,非厄米SSH链具有左趋肤效应;反之,零能附近电子透射率峰的峰值远大于1时,非厄米SSH链则具有右趋肤效应.特别是,在非平庸拓扑边缘态区域内,非厄米SSH链的趋肤效应被进一步增强.另外,当非厄米SSH链与左、右导线之间的电子隧穿耦合强度由弱到强改变时,零能附近电子反射率谷的数目将从2个变为0,此特性可以用来探测非厄米SSH链具有非平庸拓扑边缘态.上述结果在理论上为探测非厄米SSH链的非平庸拓扑边缘态和非厄米趋肤效应类型提供了一种可选择的方案.In the non-reciprocal Su-Schrieffer-Heeger(SSH)chain,the hopping amplitude of an electron in the intra-cell depends on its hopping direction.Consequently,the non-Hermitian SSH chain has both non-trivial topological edge state and non-Hermitian skin effect.However,how to detect the non-trivial topological edge states and non-Hermitian skin effect has become an important topic in non-Hermitian physics.In this paper,we study the relationships of the non-trivial topological edge states and the non-Hermitian skin effect of non-Hermitian SSH chain with their electron transport properties in the vicinity of the zero energy.It is demonstrated that when the peak value of the electron transmission probability in the vicinity of the zero energy is much smaller than 1,the non-Hermitian SSH chain has a left-non-Hermitian skin effect;while that in the vicinity of the zero energy is much larger than 1,the non-Hermitian SSH chain has a right-non-Hermitian skin effect.In particular,the skin effect of non-Hermitian SSH chain can be further enhanced in the region of non-trivial topological edge states.Moreover,with the increase of the electron tunneling coupling amplitudes between the non-Hermitian SSH chain and the left and right leads from the weak coupling regime to the strong coupling one,the number of the dips of reflection probability in the vicinity of the zero energy will change from two to zero.Therefore,these results theoretically provide an alternative scheme for detecting non-trivial topological edge states and non-Hermitian skin effect types of the non-Hermitian SSH chain.

关 键 词：边缘态 非厄米趋肤效应 非厄米Su-Schrieffer-Heeger链 反射率 透射率 

分 类 号：O469[理学—凝聚态物理]