Pfaffian Formalism for Higher-Order Topological Insulators
Pfaffian Formalism for Higher-Order Topological Insulators
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DOI：
10.1103/physrevlett.124.036401
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发表时间：
2020-01-22
影响因子：
8.6
通讯作者：
Sun, Kai
中科院分区：
文献类型：
--
作者：
Li, Heqiu;Sun, Kai
我们将在时间反演不变拓扑绝缘体（TI）研究中发挥重要作用的普法夫形式主义推广到由四重旋转对称性 C-4 和时间反演对称性 T 的乘积保护的 3D 手性高阶拓扑绝缘体（HOTI）。这种普法夫描述揭示了 TI 和 HOTI 之间深刻而基本的联系，并允许得出关于 TI 的重要结论。可以推广到 HOTI。作为示例，我们在信中演示了如何将 TI 的 Fu-Kane 奇偶校验准则推广到 HOTI，并且还提出了一种无需全局规范即可有效计算 3D 手性 HOTI 的 Z(2) 指数的通用方法。
We generalize the Pfaffian formalism, which has been playing an important role in the study of time-reversal invariant topological insulators (TIs), to 3D chiral higher-order topological insulators (HOTIs) protected by the product of fourfold rotational symmetry C-4 and the time-reversal symmetry T. This Pfaffian description reveals a deep and fundamental link between TIs and HOTIs, and allows important conclusions about TIs to be generalized to HOTIs. As examples, we demonstrate in the Letter how to generalize Fu-Kane's parity criterion for TIs to HOTIs, and also present a general method to efficiently compute the Z(2) index of 3D chiral HOTIs without a global gauge.