ELECTRONIC-STRUCTURE OF HEAZLEWOODITE NI3S2

The electronic structure of heazlewoodite Ni3S2 has been studied withi n the local-density approximation, using an extended general-potential linearized augmented-plane-wave method. The calculation indicates tha t unlike many other transition-metal sulfides and oxides, Ni3S2 is a r ather conventional metal with marginal electron-electron correlation e ffect. The electron-phonon enhancement factor similar to 0.5 is estima ted from the calculated band-structure density of states at the Fermi level and the experimental electronic specific-heat coefficient. Exami ning the charge distribution reveals metallic as well as fairly strong covalent bonding in Ni3S2.