GW quasiparticle band structures of stibnite, antimonselite, bismuthinite, and guanajuatite

摘要

We present first-principles calculations of the quasiparticle band structuresof four isostructural semiconducting metal chalcogenides A$_2$B$_3$ (with A =Sb, Bi and B = S, Se) of the stibnite family within the G$_0$W$_0$ approach. Weperform extensive convergence tests and identify a sensitivity of thequasiparticle corrections to the structural parameters and to the semicore $d$electrons. Our calculations indicate that all four chalcogenides exhibit directband gaps, if we exclude some indirect transitions marginally below the directgap. Relativistic spin-orbit effects are evaluated for the Kohn-Sham bandstructures, and included as scissor corrections in the quasiparticle band gaps.Our calculated band gaps are 1.5 eV (Sb$_2$S$_3$), 1.3 eV (Sb$_2$Se$_3$), 1.4eV (Bi$_2$S$_3$) and 0.9 eV (Bi$_2$Se$_3$). By comparing our calculated gapswith the ideal Shockley-Queisser value we find that all four chalcogenides arepromising as light sensitizers for nanostructured photovoltaics.