A new way to construct topological invariants of non-Hermitian systems with the non-Hermitian skin effect

• 来源期刊: 中国物理B（英文版）
• 关键词: non-Hermitian skin effect Su-Schrieffer-Heeger (SSH) model bulk-boundary correspondence topological invariant
• 年，卷（期）: 2020,（1）
• 页码范围: 133-138
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/ab5937

摘要

The non-Hermitian skin effect breaks the conventional bulk-boundary correspondence and leads to non-Bloch topo-logical invariants. Inspired by the fact that the topological protected zero modes are immune to perturbations, we construct a partner of a non-Hermitian system by getting rid of the non-Hermitian skin effect. Through adjusting the imbalance hopping, we find that the existence of zero-energy boundary states still dictate the bulk topological invariants based on the band-theory framework. Two non-Hermitian Su-Schrieffer-Heeger (SSH) models are used to illuminate the ideas. Spe-cially, we obtain the winding numbers in analytical form without the introduction of the generalized Brillouin zone. The work gives an alternative method to calculate the topological invariants of non-Hermitian systems.