GW calculations including spin-orbit coupling: Application to Hg chalcogenides

We present self-energy calculations for Hg chalcogenides (HgX, X = S, Se, and Te) with inverted band structures using an explicit spin-dependent formulation of the GW approximation. Spin-orbit coupling is fully taken into account in calculating the single-particle Green function G and the screened interaction W. We have found, apart from an upward shift of the occupied conductionlike Gamma(6) state by about 0.7 eV, an enhancement of spin-orbit splitting by about 0.1 eV, in good agreement with experiment. This renormalization originates mainly from spin-orbit induced changes in G rather than W, which is affected only little by spin-orbit coupling.