论文标题
结构障碍在三维中引起的二阶拓扑绝缘子
Structural Disorder Induced Second-order Topological Insulators in Three Dimensions
论文作者
论文摘要
高阶拓扑绝缘子被确定为受晶体对称性保护的拓扑结晶绝缘子。一个著名的例子是三个维度的二阶拓扑绝缘子，它托有受晶体对称性保护的手性铰链模式。由于无定形固体无处不在，因此重要的是要询问这种二阶拓扑绝缘子是否可以在无空间秩序的无定形系统中存在。在这里，我们预测无形系统中二级拓扑绝缘阶段的存在，而没有任何结晶对称性。这样的拓扑阶段在四极矩的绕组数，量化的纵向电导和铰链状态中表现出来。此外，与结构性障碍应对高阶拓扑阶段有害的观点形成鲜明对比，我们明显地发现，结构障碍可以在常规几何学中从拓扑琐碎的阶段诱导二阶拓扑绝缘子。我们最终证明了具有时间反向对称性的无定形系统中二阶拓扑阶段的存在。
Higher-order topological insulators are established as topological crystalline insulators protected by crystalline symmetries. One celebrated example is the second-order topological insulator in three dimensions that hosts chiral hinge modes protected by crystalline symmetries. Since amorphous solids are ubiquitous, it is important to ask whether such a second-order topological insulator can exist in an amorphous system without any spatial order. Here we predict the existence of a secondorder topological insulating phase in an amorphous system without any crystalline symmetry. Such a topological phase manifests in the winding number of the quadrupole moment, the quantized longitudinal conductance and the hinge states. Furthermore, in stark contrast to the viewpoint that structural disorder should be detrimental to the higher-order topological phase, we remarkably find that structural disorder can induce a second-order topological insulator from a topologically trivial phase in a regular geometry. We finally demonstrate the existence of a second-order topological phase in amorphous systems with time-reversal symmetry.
