Topological Phase Diagrams of Bulk and Monolayer TiS2−xTex

Abstract

With the use of ab initio calculations, the topological phase diagrams of bulk and monolayer TiS2−xTex are established. Whereas bulk TiS2−xTex shows two strong topological phases [1;(000)] and [1;(001)] for 0.44<x<0.56 and 0.56<x<1, respectively, the monolayer is topologically nontrivial for 0.48<x<0.80. Because in the latter doping range the topologically nontrivial nature survives down to a monolayer, TiS2−xTex is a unique system for studying topological phases in three and two dimensions simultaneously.