Prediction of wide-gap topological insulating phase in metastable BiTeI

Abstract

BiTeI crystals possess many unique pressure-induced electronic properties; however, high-pressure conditions limit their practical applications to some extent. We conducted crystal structure prediction from 3000 structures to determine several structures with high thermodynamic stability. By studying the topological invariants, we found one strong topological insulator with inversion symmetry and one weak topological insulator. Spin splitting was found in two structures, and their spin texture was analyzed by effective SOC Hamiltonian and symmetry. Our study showed that some structures are not only topologically nontrivial but can also simultaneously possess Rashba-type spin splitting with a band gap of up to 860 meV.