Higher-Order Topological Insulator on a Martini Lattice and Its Square Root Descendant
Higher-Order Topological Insulator on a Martini Lattice and Its Square Root Descendant
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DOI：
10.7566/jpsj.92.034705
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发表时间：
2022-07
影响因子：
1.7
通讯作者：
Daiki Matsumoto;T. Mizoguchi;Y. Hatsugai
中科院分区：
文献类型：
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作者：
Daiki Matsumoto;T. Mizoguchi;Y. Hatsugai
平方根拓扑绝缘体的概念最近已被推广到高阶拓扑绝缘体。在二维平方根高阶拓扑绝缘体中，带隙角态的出现继承自高阶拓扑的平方哈密顿量。在本文中，我们提出的马提尼晶格模型作为一个具体的例子，高阶拓扑绝缘体。此外，我们还提出了一个基于martini模型的平方根高阶拓扑绝缘体。具体地说，我们提出的蜂窝晶格模型与两个网站装饰，其平方哈密顿量由两个马提尼晶格模型，实现平方根高阶拓扑绝缘体。我们表明，对于这两个模型，在间隙角态出现在有限的能量，它们是由非平凡的散装$\mathbb{Z}_3$拓扑不变量。
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.