Topological phase transitions in thin films by tuning multivalley boundary-state couplings

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

5 Scopus Citations
View graph of relations


  • Xiao Li
  • Qian Niu


Original languageEnglish
Article number241411
Journal / PublicationPhysical Review B
Issue number24
Publication statusPublished - 30 Jun 2017
Externally publishedYes


Dirac boundary states on opposite boundaries can overlap and interact owing to finite size effect. We propose that in a thin film system with symmetry-unrelated valleys, valley-contrasting couplings between Dirac boundary states can be exploited to design various two-dimensional topological quantum phases. Our first-principles calculations demonstrate the mechanism in tin telluride slab and nanoribbon array, respectively, by top-down and bottom-up material designs. Both two-dimensional topological crystalline insulator and quantum spin Hall insulator emerge in the same material system, which offers highly tunable quantum transport of edge channels with a set of quantized conductances. © 2017 American Physical Society.