Ab initio study of the magnetic, optical and electronic properties of spinel Co3O4 within DFT and GW approaches

The spinel cobalt oxide Co3O4 is an antiferromagnetic semiconductor containing two non-equivalent Co2+ and Co3+ cobalt ions with different local environments and different magnetic moments. We have performed ab initio study and comparison of the electronic, magnetic and optical properties of Co(3)O(4 )within GGA, GGA + U, and G0W0 approximations. GGA correctly predicts Co3O4 to be a semiconductor, but severely underestimates the bandgap. G0W0 approximations increase the bandgap indicating a better description of the cobalt localized d-states. The spectral weights of the bands near Fermi energy are about 0.5. Ab initio calculations confirm that the low-spin state of Co3+ ion arises due to the local environment and the crystal effect field. The investigation of the pressure dependencies of magnetic properties revealed the appearance of Co3+ ion abrupt transition from low-spin state to high-spin state under tensile pressure. This allows manipulating the spin state of Co(3+ )ions through the pressure or strain.