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GW quasiparticle band structures of stibnite, antimonselite, bismuthinite, and guanajuatite
We present first-principles calculations of the quasiparticle band structures
of four isostructural semiconducting metal chalcogenides AB (with A =
Sb, Bi and B = S, Se) of the stibnite family within the GW approach. We
perform extensive convergence tests and identify a sensitivity of the
quasiparticle corrections to the structural parameters and to the semicore
electrons. Our calculations indicate that all four chalcogenides exhibit direct
band gaps, if we exclude some indirect transitions marginally below the direct
gap. Relativistic spin-orbit effects are evaluated for the Kohn-Sham band
structures, and included as scissor corrections in the quasiparticle band gaps.
Our calculated band gaps are 1.5 eV (SbS), 1.3 eV (SbSe), 1.4
eV (BiS) and 0.9 eV (BiSe). By comparing our calculated gaps
with the ideal Shockley-Queisser value we find that all four chalcogenides are
promising as light sensitizers for nanostructured photovoltaics.Comment: 11 pages, 5 figures. Revised manuscript - includes spin-orbit
interactio
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