  The electronic structure of pyrite-type cobalt phosphosulfide (CoSP) has been
studied using density-functional theory. The calculated band structure reveals
the non-magnetic semiconducting character of the compound. The electronic
structure is described through the electronic band structure and the densities
of states. A band gap of 1.14 eV has been computed within standard GGA, a value
which is enhanced using hybrid functional. It separates the upper part of the
valence band dominated by Co-3d-t2g states from the lower part of the
conduction band made exclusively of Co-3d-eg , above of which lie S-3p and P-3p
ones. The obtained values are suitable for applications in solar cells,
according to Shockley-Queisser theory of light to electric conversion
efficiency. The origin of the larger CoSP band gap, with respect to the one of
the promising FeS2 compound, is explained and the chemical bonding properties
are addressed. A comparative picture is established where several similarities
have been found, suggesting that CoSP could be for a great practical interest
in photovoltaics.
