Class of Rashba ferroelectrics in hexagonal semiconductors

We present a class of Rashba systems in hexagonal semiconducting compounds, where an electrical control over spin-orbital texture is provided by their bulk ferroelectricity. Our first-principles calculations reveal a number of such materials with large Rashba coefficients. We, furthermore, show that strain can drive a topological phase transition in such materials, resulting in a ferroelectric topological insulating state. Our findings can open avenues for interplay between Rashba effect, ferroelectricity and topological phenomena.