Insulating gap in the transition-metal oxides: A calculation using the local-spin-density approximation with the on-site CoulombUcorrelation correction

The electron-electron correlation has been considered by using the local-spin-density approximation (LSDA) with on-site Coulomb interaction (LSDA+U) in the first-principles discrete variational cluster method. Based on the correction to LSDA, we have carried out the self-consistent electronic-structure calculations for the strongly correlated electronic systems of NiO, CoO, and FeO. In contrast to LSDA, the LSDA+U calculations reveal the experimentally observed antiferromagnetic and insulating ground state. The values of the energy gap and the magnetic moment for these compounds are in good agreement with experimental results. The calculations suggest that the energy gap changes from the Mott-Hubbard characters for the early-3d-transition-metal monoxide to charge-transfer character for the late-3d-transition-metal monoxide.