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arXiv · 2207.14540

Higher-Order Topological Insulator on a Martini Lattice and Its Square Root Descendant

Daiki Matsumoto·Tomonari Mizoguchi·Yasuhiro Hatsugai
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Abstract

Notion of square-root topological insulators have been recently generalized to higher-order topological insulators. In two-dimensional square-root higher-order topological insulators, emergence of in-gap corner states are inherited from the squared Hamiltonian which hosts higher-order topology. In this paper, we propose that the martini lattice model serves as a concrete example of higher-order topological insulators. Furthermore, we also propose a suquare-root higher-order topological insulator based on the martini model. Specifically, we propose that the honeycomb lattice model with two-site decoration, whose squared Hamiltonian consists of two martini lattice models, realizes square-root higher-order topological insulators. We show, for both of these two models, that in-gap corner states appear at finite energies and that they are portected by non-trivial bulk $\mathbb{Z}_3$ topological invariant.

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Daiki Matsumoto, Tomonari Mizoguchi, Yasuhiro Hatsugai. 2022-07-29. Higher-Order Topological Insulator on a Martini Lattice and Its Square Root Descendant. https://doi.org/10.7566/jpsj.92.034705

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