Electronic States of Metal (Ti,V,Cr) Oxides

Abstract

Electronic states of metal (Ti, V, Cr) oxides were calculated by using the spin-polarized DV-Xa molecular orbital method. We adopted artificial model clusters, TiO ⁹⁻₆ , VO ⁸⁻₆ and CrO ⁷⁻₆ . For the metal ion 3d¹ configuration, we first calculated the usual case, where the lattice distortion is small. The metal 3d orbitals split into e_g and t_2g levels, and d_Xz, d_yz and d_xy orbitals are partially occupied. We second calculated the case with some possibility, where the metal-oxygen distance in the ab plane is elongated. The energy levels formed by metal 3d shift lower with increasing atomic number of metal atom. The main component of the highest occupied molecular orbital is d_xy, and states formed by d_xy are half-filled. The situation is rather similar to Cu oxides, though 0 2p hole is more important in the latter.