title: Topological phase transition in layered GaS and GaSe.
abstract: By fully relativistic first principles calculations, we predict that appropriate strain engineering of layered GaX (X=S, Se) leads to a new class of three-dimensional topological insulators with an excitation gap of up to 135 meV. Our results provide a new perspective on the formation of three-dimensional topological insulators. Band inversion can be induced by strain only, without considering any spin-orbit coupling. The latter, however, is indispensable for the formation of local band gaps at the crossing points of the inverted bands. Our study indicates that three-dimensional topological insulators can also be realized in materials which comprise light elements only.
authors.affiliation: Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhu
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Cheng
authors.forename: Udo
authors.initials: U
authors.lastname: Schwingenschlögl