Anisotropic interactions and strain-induced topological phase transition in Sb2Se3and Bi2Se3

Abstract

Based on first-principles calculations, we study the dependence of topological phase on anisotropic interactions in Bi${}_{2}$Se${}_{3}$-type materials. By applying different strains in order to vary interactions, we reveal that the topological phase is insensitive to lateral interaction but can be effectively tuned by longitudinal interaction. Longitudinal strain is inhomogeneous in the studied systems. The interquintuple interaction plays a dominant role in determining the topological phase. We explain the puzzling band-topology difference between Sb${}_{2}$Se${}_{3}$ and Bi${}_{2}$Se${}_{3}$ and propose an approach to tuning the topological phase by strain. It is found that Sb${}_{2}$Se${}_{3}$ can be converted into a topological insulator by applying compressive longitudinal strain while the converse strain can turn Bi${}_{2}$Se${}_{3}$ into a normal insulator. We have studied thin films of Sb${}_{2}$Se${}_{3}$ and Bi${}_{2}$Se${}_{3}$ and also observed a strain-induced topological phase transition.