Manipulation of the Rashba effect in layered tellurides MTe (M = Ge, Sn, Pb)

Recently, trigonal layered GeTe was exfoliated from the rhombohedral germanium telluride using a sonication-assisted liquid-phase method in experiments. We identify the blue phosphorene-like MTe (M = Ge, Sn, and Pb) monolayers and bilayers as two-dimensional semiconductors with a large Rashba-type spin-orbit coupling effect that can be modulated by the external electric field. It is found that Rashba-type spin splitting occurs around the Gamma point for both monolayer and bilayer MTe. For the bilayer MTe, we predict that the Rashba effect induced spin and momentum mismatch will give rise to a low recombination rate and long carrier lifetimes. We also obtain Rashba parameters and band gap values that are tunable with the perpendicular external electric field. In general, the low-dimensional MTe materials exhibit excellent functional characteristics, thus being promising for designing spin field-effect transistors and optoelectronic applications.