Edge States in a Thin Film of Disordered Topological Insulator
Edge States in a Thin Film of Disordered Topological Insulator
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DOI：
10.7566/jpsj.84.044701
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发表时间：
2015-03
影响因子：
1.7
通讯作者：
K. Hattori
中科院分区：
文献类型：
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作者：
K. Hattori
磁性拓扑绝缘体（TI）薄膜的几何结构根据薄膜的厚度和磁耦合的强度改变其拓扑性质，并且可以表现出量子自旋霍尔（QSH）效应以及量子反常霍尔（QAH）效应。在这项研究中，我们追求一个定量调查的影响，薄膜TI在所有可能的拓扑阶段的无序。结果表明，足够强的无序诱导拓扑相变，并普遍创建具有QSH相特征的金属螺旋边缘状态之前，所有的电子状态最终被本地化。在热力学极限下，无序诱导的QSH相的定域-离域跃迁属于具有非平凡陈数的幺正普适类。在有限大小的系统中，拓扑保护的边缘状态持续存在，除非迁移率间隙崩溃。它还表明，边缘状态延伸超过宏观距离的中间…
A thin-film geometry of nonmagnetic or magnetic topological insulator (TI) alters its topological properties depending on the thickness of the film and the strength of the magnetic coupling, and can exhibit the quantum spin Hall (QSH) effect as well as the quantum anomalous Hall (QAH) effect. In this study, we pursue a quantitative investigation of effects of nonmagnetic disorder on thin-film TIs in all the possible topological phases. The results show that strong enough disorder induces a topological phase transition and generically creates metallic helical edge states featuring the QSH phase before all electronic states are eventually localized. In the thermodynamic limit, the localization–delocalization transition in the disorder-induced QSH phase is in the unitary universality class with nontrivial Chern numbers. In a finite-size system, topologically protected edge states persist unless the mobility gap collapses. It is also demonstrated that edge states extend over a macroscopic distance in the midd...