A scheme for realizing nonreciprocal interlayer coupling in bilayer topological systems  

作　　者：Xiaoxiao Wang Ruizhe Gu Yandong Li Huixin Qi Xiaoyong Hu Xingyuan Wang Qihuang Gong 

机构地区：[1]State Key Laboratory for Mesoscopic Physics and Department of Physics,Collaborative Innovation Center of Quantum Matter&Frontiers Science Center for Nano-Optoelectronics,Beijing Academy of Quantum Information Sciences,Peking University,Beijing 100871,China [2]Peking University Yangtze Delta Institute of Optoelectronics,Nantong 226010,China [3]Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China [4]Hefei National Laboratory,Hefei 230088,China [5]College of Mathematics and Physics,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Frontiers of Optoelectronics》2023年第4期71-80,共10页光电子前沿（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.91950204,92150302,and 62175009);Innovation Program for Quantum Science and Technology(No.2021ZD0301500);Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(No.KF202114).

摘　　要：Nonreciprocal interlayer coupling is difcult to practically implement in bilayer non-Hermitian topological photonic systems.In this work,we identify a similarity transformation between the Hamiltonians of systems with nonreciprocal interlayer coupling and on-site gain/loss.The similarity transformation is widely applicable,and we show its application in one-and two-dimensional bilayer topological systems as examples.The bilayer non-Hermitian system with nonreciprocal interlayer coupling,whose topological number can be defned using the gauge-smoothed Wilson loop,is topologically equivalent to the bilayer system with on-site gain/loss.We also show that the topological number of bilayer non-Hermitian C6v-typed domaininduced topological interface states can be defned in the same way as in the case of the bilayer non-Hermitian Su–Schrieffer–Heeger model.Our results show the relations between two microscopic provenances of the non-Hermiticity and provide a universal and convenient scheme for constructing and studying nonreciprocal interlayer coupling in bilayer non-Hermitian topological systems.This scheme is useful for observation of non-Hermitian skin efect in three-dimensional systems.

关 键 词：Nonreciprocal BILAYER Interlayer coupling Topological photonics 

分 类 号：O48[理学—固体物理]