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Quasiparticle band structures of β -HgS, HgSe, and HgTe

2011; American Physical Society; Volume: 84; Issue: 20 Linguagem: Inglês

10.1103/physrevb.84.205205

1550-235X

A. Svane, N. E. Christensen, M. Cardona, A. N. Chantis, Mark van Schilfgaarde, Takao Kotani,

Topological Materials and Phenomena

The electronic structures of mercury chalcogenides in the zinc-blende structure have been calculated within the LDA, $GW$ ($G$${}_{0}$$W$${}_{0}$, ``one-shot'') and quasi-particle self-consistent $GW$ ($\text{QS}GW$) approximations, including spin-orbit (SO) coupling. The slight tendency to overestimation of band gaps by $\text{QS}GW$ is avoided by using a hybridscheme (20$%$ LDA and 80$%$ $\text{QS}GW$). The details of the $GW$ bands near the top of the valence bands differ significantly from the predictions obtained by calculations within the LDA. The results obtained by ${G}_{0}{W}_{0}$ depend strongly on the starting wave functions and are thus quite different from those obtained from QS$GW$. Within $\text{QS}GW$, HgS is found to be a semiconductor, with a ${\ensuremath{\Gamma}}_{6}$ $s$-like conduction-band minimum state above the valence top ${\ensuremath{\Gamma}}_{7}$ and ${\ensuremath{\Gamma}}_{8}$ (``negative'' SO splitting). HgSe and HgTe have negative gaps (inverted band structures), but for HgTe the ${\ensuremath{\Gamma}}_{7}$ state is below ${\ensuremath{\Gamma}}_{6}$ due to the large Te SO splitting, in contrast to HgSe where ${\ensuremath{\Gamma}}_{6}$ is below ${\ensuremath{\Gamma}}_{7}$. There appears to be significant differences, in particular for HgSe and HgS, between the ordering of the band-edge states as obtained from experiments and theory.