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 Γ 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.