Density of States Scaling at the Semimetal to Metal Transition in Three Dimensional Topological Insulators
Density of States Scaling at the Semimetal to Metal Transition in Three Dimensional Topological Insulators
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DOI：
10.1103/physrevlett.112.016402
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发表时间：
2014-01-07
影响因子：
8.6
通讯作者：
Herbut, Igor F.
中科院分区：
文献类型：
--
作者：
Kobayashi, Koji;Ohtsuki, Tomi;Herbut, Igor F.
增加无序度可以诱导三维狄拉克半金属与扩散金属之间的量子相变。以无序Z(2)拓扑绝缘子系统为例，用核多项式方法计算了系统的单粒子态密度。我们重点研究了三个区域：两个拓扑不同相之间的Dirac半金属，两个拓扑绝缘体相和扩散金属的三临界点，以及处于强无序状态的扩散金属。态密度服从一种新的单参数标度，坍缩到一个通用标度函数的两个分支上，这两个分支对应于狄拉克半金属和扩散金属。对发散长度尺度临界指数nu和动态临界指数z进行了估计，发现它们与传统的Anderson跃迁有显著差异。讨论了实验观测量在临界点附近和三临界点处的临界行为。
The quantum phase transition between the three dimensional Dirac semimetal and the diffusive metal can be induced by increasing disorder. Taking the system of a disordered Z(2) topological insulator as an important example, we compute the single particle density of states by the kernel polynomial method. We focus on three regions: the Dirac semimetal at the phase boundary between two topologically distinct phases, the tricritical point of the two topological insulator phases and the diffusive metal, and the diffusive metal lying at strong disorder. The density of states obeys a novel single parameter scaling, collapsing onto two branches of a universal scaling function, which correspond to the Dirac semimetal and the diffusive metal. The diverging length scale critical exponent nu and the dynamical critical exponent z are estimated, and found to differ significantly from those for the conventional Anderson transition. Critical behavior of experimentally observable quantities near and at the tricritical point is also discussed.