We present an analysis of bulk and surface electronic structures of thallium-based ternary III-V-VI 2 series of compounds TlMQ 2, where M=Bi or Sb and Q=S, Se, or Te, using the ab initio density functional theory framework. Based on parity analysis and (111) surface electronic structure, we predict TlSbSe 2, TlSbTe 2, TlBiSe 2, and TlBiTe 2 to be nontrivial topological insulators with a single Dirac cone at the Γ point and TlSbS 2 and TlBiS 2 to be trivial band insulators. Our predicted topological phases agree well with available angle-resolved photoemission spectroscopy measurements, in particular, the topological phase changes between TlBiSe 2 and TlBiS 2. Moreover, we propose that Weyl semimetal can be realized at the topological critical point in TlBi(S 1-xSe x) 2 and TlBi(S 1-xTe x) 2 alloys by breaking the inversion symmetry in the layer-by-layer growth in the order Tl-Se(Te)-Bi-S, yielding six Dirac cones centered along the Γ-L directions in the bulk band structure.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Sep 18 2012|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics