Higher-order topological insulators protected by inversion and rotoinversion symmetries
Higher-order topological insulators protected by inversion and rotoinversion symmetries
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DOI：
10.1103/physrevb.98.081110
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发表时间：
2018-06
影响因子：
3.7
通讯作者：
Guido van Miert;C. Ortix
中科院分区：
文献类型：
--
作者：
Guido van Miert;C. Ortix
我们提供了手性高阶拓扑绝缘体的体拓扑不变量（i）四重旋转反转不变体晶体，以及（ii）具有或不具有附加三重旋转对称性的反演对称系统。这些物质状态的特征是一个不平凡的 ${\mathbb{Z}}_{2}$ 指数，我们根据填充能带的对称杂化万尼尔函数来定义该指数，并且可以根据体能带结构的晶体对称标签的知识轻松计算。拓扑不变量决定了位于常规带隙表面之间的铰链处的受保护手性无间隙一维模式的一般存在或不存在。
We provide the bulk topological invariant for chiral higher-order topological insulators in (i) fourfold rotoinversion invariant bulk crystals, and (ii) inversion-symmetric systems with or without an additional threefold rotation symmetry. These states of matter are characterized by a nontrivial ${\mathbb{Z}}_{2}$ index, which we define in terms of symmetric hybrid Wannier functions of the filled bands, and can be readily calculated from the knowledge of the crystalline symmetry labels of the bulk band structure. The topological invariant determines the generic presence or absence of protected chiral gapless one-dimensional modes localized at the hinges between conventional gapped surfaces.