edge state of Non-Hermitian SSH model

Iao Fai Io^1*, Cheng Yuan Huang¹, Hsien Chung Kao¹

¹Physics Department, National Taiwan Normal University, Taipei 11677, Taiwan

* Presenter:Iao Fai Io, email:jacky_r4@hotmail.com

Su Schrieffer Heeger (SSH) model is the simplest 1D topological model, which is classified by the 1D winding number. When the winding number in non-vanishing, the system would be in the topological phase and edge states would appear on the boundaries of the system. This is the so-called bulk edge correspondence. In this poster we will focus on the non-Hermitian (NH) SSH model and its extended version. Since the system is NH, there might exist exceptional points (EPs) in the system. When this occurs, the system becomes defective and the number of energy eigenstates is not equal to the dimension of the Hamiltonian. Nevertheless, bulk edge correspondence is still valid in the NH SSH model. The condition for the appearance of EPs in both models may be found analytically, which may be exploited to discuss the properties of the EPs in details.

Keywords: Non-Hermitian SSH model, Bulk edge correspondence, Exceptional point