Phys. Rev. B 105, 125103 (2022)
Hermitian chiral boundary states in non-Hermitian topological insulators
C. Wang1,* and X. R. Wang2,3,†
1 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300350, China
2 Physics Department, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong
3 HKUST Shenzhen Research Institute, Shenzhen 518057, China
* Corresponding author: physcwang@tju.edu.cn
† Corresponding author: phxwan@ust.hk
Abstract
Eigenenergies of a non-Hermitian system without parity-time symmetry are complex in general. Here, we show that the chiral boundary states of higher-dimensional non-Hermitian topological insulators without parity-time symmetry can be Hermitian with real eigenenergies under certain conditions. Our approach allows one to construct Hermitian chiral edge and hinge states from non-Hermitian two-dimensional Chern insulators and three-dimensional second-order topological insulators, respectively. Such Hermitian chiral boundary channels have perfect transmission coefficients (quantized values) and are robust against disorders. Furthermore, a non-Hermitian topological insulator can undergo the topological Anderson insulator transition from a topologically trivial non-Hermitian metal or insulator to a topological Anderson insulator with quantized transmission coefficients at finite disorders.
