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arXiv · 2102.12189

Real space topological invariant and higher-order topological Anderson insulator in two-dimensional non-Hermitian systems

Hongfang Liu·Ji-Kun Zhou·Bing-Lan Wu·Zhi-Qiang Zhang·Hua Jiang
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Abstract

We study the characterization and realization of higher-order topological Anderson insulator (HOTAI) in non-Hermitian systems, where the non-Hermitian mechanism ensures extra symmetries as well as gain and loss disorder.We illuminate that the quadrupole moment $Q_{xy}$ can be used as the real space topological invariant of non-Hermitian higher-order topological insulator (HOTI). Based on the biorthogonal bases and non-Hermitian symmetries, we prove that $Q_{xy}$ can be quantized to $0$ or $0.5$. Considering the disorder effect, we find the disorder-induced phase transition from normal insulator to non-Hermitian HOTAI. Furthermore, we elucidate that the real space topological invariant $Q_{xy}$ is also applicable for systems with the non-Hermitian skin effect. Our work enlightens the study of the combination of disorder and non-Hermitian HOTI.

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Hongfang Liu, Ji-Kun Zhou, Bing-Lan Wu, Zhi-Qiang Zhang, Hua Jiang. 2021-02-24. Real space topological invariant and higher-order topological Anderson insulator in two-dimensional non-Hermitian systems. https://doi.org/10.1103/physrevb.103.224203

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