Quantum spin Hall effect in two-dimensional transition metal dichalcogenides

Quantum spin Hall (QSH) effect materials feature edge states that are topologically protected from backscattering. However, the small band gap in materials that have been identified as QSH insulators limits applications. We use first-principles calculations to predict a class of large-gap QSH insulators in two-dimensional transition metal dichalcogenides with 1T' structure, namely, 1T'-MX2 with M = (tungsten or molybdenum) and X = (tellurium, selenium, or sulfur). A structural distortion causes an intrinsic band inversion between chalcogenide-p and metal-d bands. Additionally, spin-orbit coupling opens a gap that is tunable by vertical electric field and strain. We propose a topological field effect transistor…

• NS
  National Science Foundation

  Awards: 1231319, DMR-1120901, 1120901, TG-DMR130038
• UD
  U.S. Department of Energy

  Award: DMR-1231319
• DO
  Division of Materials Research

  Awards: 1231319, TG-DMR130038, 1120901, DMR-1120901, DMR-1231319
• BE
  Basic Energy Sciences
• DO
  Division of Materials Sciences and Engineering