arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2303.04031cond-mat.mes-hall
收藏

偶数自旋陈数高阶拓扑绝缘体中的时间反演孤子对

Time-Reversal Soliton Pairs In Even Spin-Chern-Number Higher-Order Topological Insulators

Yi-Chun Hung, Baokai Wang, Chen-Hsuan Hsu, Arun Bansil, Hsin Lin

AI总结:

本研究针对现有时间反演对称系统边缘孤子研究不适用于常见自旋陈绝缘体的问题,聚焦自旋陈数为2的绝缘体,通过质量扭折机制解释成对角模式与额外电荷的产生,证明偶数自旋陈数绝缘体是带受保护角落电荷的高阶拓扑绝缘体。

摘要:

在具有非平凡拓扑的二维系统边缘,通过一维质量扭折机制形成的孤子对高阶(HO)拓扑相的出现具有重要作用。在这一研究方向中,现有时间反演对称系统的研究聚焦于在粒子-空穴对称存在的情况下使边缘狄拉克锥打开能隙,这并不适用于常见的自旋陈绝缘体。本文研究了自旋陈数为2的绝缘体中边缘孤子的出现,其中边缘狄拉克锥通过保持时间反演对称性但破缺自旋-U(1)对称性的微扰打开能隙。通过质量扭折机制,我们解释了成对角模式的出现,并预测了角落周围额外电荷的产生。通过追踪质量项沿边缘的演化,我们证明了能隙内的角模式及相关额外电荷可通过S_z混合自旋轨道耦合经由质量扭折机制产生。由此我们提供了有力证据,表明偶数自旋陈数绝缘体是一种具有受保护角落电荷的高阶(HO)拓扑绝缘体。

英文摘要:

Solitons formed through the one-dimensional mass-kink mechanism on the edges of two-dimensional systems with non-trivial topology play an important role in the emergence of higher-order (HO) topological phases. In this connection, the existing work in time-reversal symmetric systems has focused on gapping the edge Dirac cones in the presence of particle-hole symmetry, which is not suited to the common spin-Chern insulators. Here, we address the emergence of edge solitons in spin-Chern number of $2$ insulators, in which the edge Dirac cones are gapped by perturbations preserving time-reversal symmetry but breaking spin-$U(1)$ symmetry. Through the mass-kink mechanism, we thus explain the appearance of pairwise corner modes and predict the emergence of extra charges around the corners. By tracing the evolution of the mass term along the edge, we demonstrate that the in-gap corner modes and the associated extra charges can be generated through the $S_z$-mixing spin-orbit coupling via the mass-kink mechanism. We thus provide strong evidence that an even spin-Chern-number insulator is an HO topological insulator with protected corner charges.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑