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arXiv 1906.04700cond-mat.mes-hall
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广义非互易Su-Schrieffer-Heeger模型的拓扑不变量、零模边缘态和有限尺寸效应

Topological invariants, zero mode edge states and finite size effect for a generalized non-reciprocal Su-Schrieffer-Heeger model

Hui Jiang, Rong Lü, Shu Chen

摘要:

一维非互惠拓扑系统中有趣的问题包括通常的体边对应的崩溃和半整数拓扑不变量的出现。为了理解这些不寻常的拓扑性质,我们研究的拓扑相图和零模边缘状态的推广的非互易Su-Schrieffer-Heeger模型的基础上,一些分析结果。同时,我们提供了一个简洁的几何解释的体积拓扑不变量的两个独立的缠绕数,也给出了另一种解释有关的连接性质的曲线在三维空间。对于开边界条件下的系统,我们通过适当考虑系统的隐对称性和归一化条件,利用双正交本征向量,解析地构造了零模边缘态的波函数。我们的分析结果直接给出了零模边缘态存在的相边界,清晰地揭示了边缘态的演化行为。通过与有限尺寸系统精确对角化的结果比较,我们发现我们的解析结果与数值结果吻合得很好。

英文摘要:

Intriguing issues in one-dimensional non-reciprocal topological systems include the breakdown of usual bulk-edge correspondence and the occurrence of half-integer topological invariants. In order to understand these unusual topological properties, we investigate the topological phase diagrams and the zero-mode edge states of a generalized non-reciprocal Su-Schrieffer-Heeger model, based on some analytical results. Meanwhile, we provide a concise geometrical interpretation of the bulk topological invariants in terms of two independent winding numbers and also give an alternative interpretation related to the linking properties of curves in three-dimensional space. For the system under the open boundary condition, we construct analytically the wavefunctions of zero-mode edge states by properly considering a hidden symmetry of the system and the normalization condition with the use of biorthogonal eigenvectors. Our analytical results directly give the phase boundary for the existence of zero-mode edge states and unveil clearly the evolution behavior of edge states. In comparison with results via exact diagonalization of finite-size systems, we find our analytical results agree with the numerical results very well.

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