Topological invariant in three-dimensional band insulators with disorder
Topological invariant in three-dimensional band insulators with disorder
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DOI：
10.1103/physrevb.82.115122
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发表时间：
2010-09-27
影响因子：
3.7
通讯作者：
Guo, H. -M.
中科院分区：
文献类型：
--
作者：
Guo, H. -M.
三维拓扑绝缘体由一个Z（2）值拓扑不变量刻画，它由一个强指数和三个弱指数组成.在无序的情况下，只有强指数存在。本文将三维无序系统看作无限周期系统的超胞，研究其拓扑不变量。作为该方法的一个应用，我们证明了当引入足够强的无序到具有自旋轨道耦合的平凡绝缘体中时，强指数变得非平凡，实现了强拓扑安德森绝缘体。数值计算得到了该拓扑相的差距范围和相边界，与自洽玻恩近似和输运计算结果吻合较好.
Topological insulators in three dimensions are characterized by a Z(2)-valued topological invariant, which consists of a strong index and three weak indices. In the presence of disorder, only the strong index survives. This paper studies the topological invariant in disordered three-dimensional system by viewing it as a supercell of an infinite periodic system. As an application of this method we show that the strong index becomes nontrivial when strong enough disorder is introduced into a trivial insulator with spin-orbit coupling, realizing a strong topological Anderson insulator. We also numerically extract the gap range and determine the phase boundaries of this topological phase, which fits well with those obtained from self-consistent Born approximation and the transport calculations.