中国物理B ›› 2023, Vol. 32 ›› Issue (2): 20305-020305.doi: 10.1088/1674-1056/ac9046

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

Junjie Wang(王俊杰)1, Fude Li(李福德)1, and Xuexi Yi(衣学喜)1,2,†   

  1. 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
  • 收稿日期:2022-03-08 修回日期:2022-08-17 接受日期:2022-09-08 出版日期:2023-01-10 发布日期:2023-01-31
  • 通讯作者: Xuexi Yi E-mail:yixx@nenu.edu.cn
  • 基金资助:
    The authors acknowledge Hongzhi Shen and Weijun Cheng for helpful comments. This work was supported by the National Natural Science Foundation of China (Grant Nos. 12175033 and 12147206).

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

Junjie Wang(王俊杰)1, Fude Li(李福德)1, and Xuexi Yi(衣学喜)1,2,†   

  1. 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
  • Received:2022-03-08 Revised:2022-08-17 Accepted:2022-09-08 Online:2023-01-10 Published:2023-01-31
  • Contact: Xuexi Yi E-mail:yixx@nenu.edu.cn
  • Supported by:
    The authors acknowledge Hongzhi Shen and Weijun Cheng for helpful comments. This work was 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

Abstract: 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.

Key words: Hall conductance, non-Hermitian, topological insulators

中图分类号:  (Phases: geometric; dynamic or topological)

  • 03.65.Vf