宇称-时间反演对称的Su-Schrieffer-Heeger模型的拓扑特性

摘要

尽管一类具有宇称和时间反演联合对称性的模型是非厄米的,然而在某些参数区域内系统能谱具有全实数的特征,引起了人们极大的兴趣,特别是此类系统的拓扑性质已经成为了研究热点.Su-Schrieffer-Heeger(SSH)模型作为最简单的拓扑绝缘体模型,引入平衡的增益和损耗的化学势,成为具有宇称-时间反演对称的SSH模型.通过研究系统的能谱,找到宇称-时间反演对称破缺点,发现在宇称-时间反演对称性未破缺区域,系统的拓扑性质与未引入非厄米的化学势的系统相类似.%Although the model with parity-time reversal (PT) symmetry is non-Hermition,the energy spectra of the system in some regions are all real,which is greatly fascinating.Especially,the topological properties of these systems have been hotspots.As the simplest topological insulator model,Su-Schrieffer-Heeger(SSH) model is added by the balance gain and loss chemical potential,which becomes the SSH model with PT symmetry.By studying the energy spectra of the system,the PT symmetry broken point can be found.It is found that topological properties of the system in unbroken region are similar to those of the system without non-Hermition chemical potential.