Electronic structure of perovskite-type transition metal oxides LaMO3 (M=Ti∼Cu) by U plus GW approximation

We investigate electronic structures of LaMO3 (M=Ti similar to Cu) systematically by means of U+GW approximation. In these strongly correlated systems, it is important to treat large on-site Coulomb interactions and their dynamical screening effects. Transition-metal ions in perovskite-type lanthanum oxides are trivalent and their physics is qualitatively different from that of divalent transition-metal ions in transition-metal mono-oxides. The localization of wave functions of La 4f and 3d orbitals of Ti, V, and Co is crucial. On the other hand, the screening effect for other transition-metal 3d orbitals is strong enough so as to reduce the on-site static-screened Coulomb interaction in trivalent oxides. The band gaps, the magnetic moments, and energy spectra are discussed in comparison with the experimentally observed results. Calculated energy spectra of LaMO3 (M=V similar to Cu) are in good agreement with experimental results.