论文标题
Floquet拓扑绝缘子中的异常和正常位错模式
Anomalous and normal dislocation modes in Floquet topological insulators
论文作者
论文摘要
具有非平凡散装拓扑不变的电子带通过边界处的强大无间隙模式（例如边缘和表面）表现出来。因此，这种散装边界的对应关系在驱动的量子材料中也是可行的。例如，合适的周期性驱动器可以将微不足道的绝缘子转换为浮光拓扑绝缘子（FTI），该绝缘子（FTI）可容纳与真空接口的非隔离动态无间隙模式。从理论上讲，在这里，我们证明了晶体中普遍存在的晶格缺陷的位错，可以通过支持正常和异常模式来探测大部分驱动量子系统中的非常规$π$ ditivial的绝缘子，该模式位于缺陷核附近。正常和异常位错模式分别存在于浮球区中心和边界。我们专门针对二维（2D）浮雕Chern绝缘子和$ p_x+ip_y $ superconductor的这些结果举例说明了这些结果，其中脱位模式分别由带电和中性的Majorana fermions组成。因此，我们的发现应在驱动的量子晶体，冷原子设置以及光子和语音超材料中通过散装拓扑晶格缺陷进行最先进的实验中的浮雕拓扑阶段发挥作用。
Electronic bands featuring nontrivial bulk topological invariant manifest through robust gapless modes at the boundaries, e.g., edges and surfaces. As such this bulk-boundary correspondence is also operative in driven quantum materials. For example, a suitable periodic drive can convert a trivial insulator into a Floquet topological insulator (FTI) that accommodates nondissipative dynamic gapless modes at the interfaces with vacuum. Here we theoretically demonstrate that dislocations, ubiquitous lattice defects in crystals, can probe FTIs as well as unconventional $π$-trivial insulator in the bulk of driven quantum systems by supporting normal and anomalous modes, localized near the defect core. Respectively, normal and anomalous dislocation modes reside at the Floquet zone center and boundaries. We exemplify these outcomes specifically for two-dimensional (2D) Floquet Chern insulator and $p_x+ip_y$ superconductor, where the dislocation modes are respectively constituted by charged and neutral Majorana fermions. Our findings should be therefore instrumental in probing Floquet topological phases in the state-of-the-art experiments in driven quantum crystals, cold atomic setups, and photonic and phononic metamaterials through bulk topological lattice defects.
