论文标题
Creutz梯子中的高阶拓扑
Higher order topology in a Creutz ladder
论文作者
论文摘要
Creutz梯子是一个准单维系统，其托管可靠的拓扑阶段，其局部边缘模式受不同对称性（例如反转，手性和颗粒 - 孔孔对称性）保护的局部边缘模式。在由水平，对角线和垂直跳动的隔离度定义的参数空间的大区域中观察到非平凡的拓扑，以及穿过梯子的横向磁通量。在这项工作中，我们在Creutz梯子的二维外推版中研究了高阶拓扑。为了探索拓扑阶段，我们考虑了两种不同的配置，即圆环（周期性边界）和一个色带（开放边界），以查找间隙闭合相变的提示。我们还将合适的拓扑不变性与非平凡部门相关联。此外，我们发现所得相图具有两个不同的拓扑阶段，一个阶段是以稳健的角模式的形式实现高阶拓扑激发，以及（通常）通过有限晶格中的边缘模式存在的（通常）一阶兴奋。
A Creutz ladder, is a quasi one dimensional system hosting robust topological phases with localized edge modes protected by different symmetries such as inversion, chiral and particle-hole symmetries. Non-trivial topology is observed in a large region of the parameter space defined by the horizontal, diagonal and vertical hopping ampitudes and a transverse magnetic flux that threads through the ladder. In this work, we investigate higher order topology in a two dimensional extrapolated version of the Creutz ladder. To explore the topological phases, we consider two different configurations, namely a torus (periodic boundary) and a ribbon (open boundary) to look for hints of gap closing phase transitions. We also associate suitable topological invariants to characterize the non-trivial sectors. Further, we find that the resultant phase diagram hosts two different topological phases, one where the higher order topological excitations are realized in the form of robust corner modes, along with (usual) first order excitations demonstrated via the presence of edge modes in a finite lattice, for the other.
