Hall conductance of a non-Hermitian two-band system with k-dependent decay rates  

作　　者：王俊杰 李福德 衣学喜 Junjie Wang;Fudu Li;Xuexi Yi(Center for Quantum Sciences and School of Physics,Northeast Normal University,Changchun 130024,China;Center for Advanced Optoelectronic Functional Materials Research,and Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education,Northeast Normal University,Changchun 130024,China)

机构地区：[1]Center for Quantum Sciences and School of Physics,Northeast Normal University,Changchun 130024,China [2]Center for Advanced Optoelectronic Functional Materials Research,and Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education,Northeast Normal University,Changchun 130024,China

出　　处：《Chinese Physics B》2023年第2期108-116,共9页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 12175033 and 12147206)。

摘　　要：Two-band model works well for Hall effect in topological insulators. It turns out to be non-Hermitian when the system is subjected to environments, and its topology characterized by Chern numbers has received extensive studies in the past decades. However, how a non-Hermitian system responses to an electric field and what is the connection of the response to the Chern number defined via the non-Hermitian Hamiltonian remains barely explored. In this paper, focusing on a k-dependent decay rate, we address this issue by studying the response of such a non-Hermitian Chern insulator to an external electric field. To this aim, we first derive an effective non-Hermitian Hamiltonian to describe the system and give a specific form of k-dependent decay rate. Then we calculate the response of the non-Hermitian system to a constant electric field.We observe that the environment leads the Hall conductance to be a weighted integration of curvature of the ground band and hence the conductance is no longer quantized in general. And the environment induces a delay in the response of the system to the electric field. A discussion on the validity of the non-Hermitian model compared with the master equation description is also presented.

关 键 词：Hall conductance NON-HERMITIAN topological insulators 

分 类 号：O469[理学—凝聚态物理]