Dynamical Singularities of Floquet Higher-Order Topological Insulators
Dynamical Singularities of Floquet Higher-Order Topological Insulators
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DOI：
10.1103/physrevlett.124.057001
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发表时间：
2020-02-03
影响因子：
8.6
通讯作者：
Liu, W. Vincent
中科院分区：
文献类型：
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作者：
Hu, Haiping;Huang, Biao;Liu, W. Vincent
我们提出了一个通用的框架，动态生成Floquet高阶拓扑绝缘体的多步驱动拓扑平凡的哈密顿。两个解析可解的例子来说明这个过程中产生Floquet四极和八极绝缘体与零和/或π角模式保护镜对称性。此外，我们从全么正返回映射中引入动力学拓扑不变量，并证明其相带包含Weyl奇点，其拓扑荷在布里渊区形成动力学多极矩。将它们与Floquet Hamilton算子的拓扑指数相结合，给出了一对Z（2）不变量nu（0）和nu（pi），它们完全表征了高阶拓扑，并预测了零角模和π角模的出现。我们的工作建立了一个系统的路线来构建和表征Floquet高阶拓扑相位。
We propose a versatile framework to dynamically generate Floquet higher-order topological insulators by multistep driving of topologically trivial Hamiltonians. Two analytically solvable examples are used to illustrate this procedure to yield Floquet quadrupole and octupole insulators with zero- and/or pi-corner modes protected by mirror symmetries. Furthermore, we introduce dynamical topological invariants from the full unitary return map and show its phase bands contain Weyl singularities whose topological charges form dynamical multipole moments in the Brillouin zone. Combining them with the topological index of a Floquet Hamiltonian gives a pair of Z(2) invariant nu(0) and nu(pi) which fully characterize the higher-order topology and predict the appearance of zero- and pi-corner modes. Our work establishes a systematic route to construct and characterize Floquet higher-order topological phases.