Disorder-induced multiple transition involving ℤ2 topological insulator

Ai Yamakage, Kentaro Nomura, Ken Ichiro Imura, Yoshio Kuramoto

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

Effects of disorder on two-dimensional ℤ2 topological insulator are studied numerically by the transfer matrix method. Based on the scaling analysis, the phase diagram is derived for a model of HgTe quantum well as a function of disorder strength and magnitude of the energy gap. In the presence of sz non-conserving spin-orbit coupling, a finite metallic region is found that partitions the two topologically distinct insulating phases. As disorder increases, a narrow-gap topologically trivial insulator undergoes a series of transitions; first to metal, second to topological insulator, third to metal, and finally back to trivial insulator. We show that this multiple transition is a consequence of two disorder effects; renormalization of the band gap, and Anderson localization. The metallic region found in the scaling analysis corresponds roughly to the region of finite density of states at the Fermi level evaluated in the self-consistent Born approximation.

Original languageEnglish
Article number053703
Journaljournal of the physical society of japan
Volume80
Issue number5
DOIs
Publication statusPublished - 2011 May

Keywords

  • Density of states
  • Disorder
  • HgTe
  • Phase diagram
  • Self-consistent Born approximation
  • Transfer matrix
  • ℤ topological insulator

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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