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

TL;DR

This study uses first-principles G0W0 calculations to determine the quasiparticle band structures of four semiconducting metal chalcogenides, revealing their potential for photovoltaic applications.

Contribution

The paper provides detailed G0W0 quasiparticle band structures of four isostructural chalcogenides, including convergence tests and spin-orbit effects, which were previously not comprehensively reported.

Findings

All four materials have direct band gaps close to the calculated values.

Calculated band gaps suggest suitability for nanostructured photovoltaics.

Relativistic effects slightly modify the quasiparticle band gaps.

Abstract

We present first-principles calculations of the quasiparticle band structures of 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. We perform extensive convergence tests and identify a sensitivity of the quasiparticle corrections to the structural parameters and to the semicore $d$ 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 (Sb$_2$S$_3$), 1.3 eV (Sb$_2$Se$_3$), 1.4 eV (Bi$_2$S$_3$) and 0.9 eV (Bi$_2$Se$_3$). 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.