Taming the ground-state and optical properties of transition metal oxides

We have implemented the so-called local density approximation (LDA) plus the Hubbard parameter U method (LDA+U), in a formalism based on the projector augmented wave (PAW) method and calculated the ground-state properties of NiO and its optical properties. Good agreement with the measured ground-state antiferromagnetic magnetic moment and optical properties are obtained for U=5 eV. The enhancement of the O 2p near the top of the valence states increases with the value of U. At intermediate U, the nature of the band gap is a mixture of charge transfer and Ni d → d excitations.