论文标题
在二维晶体绝缘子中的角状态的拓扑免疫力上
On the topological immunity of corner states in two-dimensional crystalline insulators
论文作者
论文摘要
二维中的高阶拓扑绝缘子（HOTI）是一个没有金属边缘状态的绝缘体，但具有稳健的零维拓扑边界模式，位于其角落。然而，这些角模式并未具有其拓扑的明确签名，因为它们缺乏螺旋形或手性边界状态的异常性。在这里，我们使用免疫测试证明，在呼吸kagome晶格中发现的角模式代表了错误的身份的主要例子。与以前的理论和实验性主张相反，我们表明这些角模式本质上是脆弱的：kagome晶格没有意识到高阶拓扑绝缘子。我们通过基于基于角度电荷模式对应的标准来支持这一发现，该标准是在N折旋转对称性手性绝缘子中存在拓扑Midgap角模式的，该模式明确地排除了由三倍旋转对称性保护的HOTI的存在。
A higher-order topological insulator (HOTI) in two dimensions is an insulator without metallic edge states but with robust zero-dimensional topological boundary modes localized at its corners. Yet, these corner modes do not carry a clear signature of their topology as they lack the anomalous nature of helical or chiral boundary states. Here, we demonstrate using immunity tests that the corner modes found in the breathing kagome lattice represent a prime example of a mistaken identity. Contrary to previous theoretical and experimental claims, we show that these corner modes are inherently fragile: the kagome lattice does not realize a higher-order topological insulator. We support this finding by introducing a criterion based on a corner charge-mode correspondence for the presence of topological midgap corner modes in n-fold rotational symmetric chiral insulators that explicitly precludes the existence of a HOTI protected by a threefold rotational symmetry.
