Fig. 2: Effect of DFT approximations and V4 cluster state on the band gap.

Density of states of GaV4S8 calculated within density functional theory in (a, b) LDA and (c, d) GGA approximations without and with Hubbard-U corrections. Red and blue curves correspond to spin-up and -down states. The system is in the localized-moment semi-metallic state in GGA at U = 0 eV (no bands cross EF, but the energy gap is zero valued) and is semiconducting at U = 2 eV (plots b and d) with a gap Eg = 0.2 eV (localized-moment state, dark lines) and 0.3 eV (distributed-moment state, light lines).