Surface and Bulk Electronic Properties of D-Band Perovskites.

The surface and bulk electronic structures of cubic d-band perovskites were calculated using a semiempirical LCAO model which included the p-orbitals of the oxygen ions and the d-orbitals of the transition metal ions. It is found that the surface states are forced out of the band-gap region by the intraatomic Coulomb interaction among excess electrons on surface cation sites. Analytical formulae for the electronic density of states were derived including all of the fourteen primary energy bands of the cubic perovskites. The theoretical results are shown to be in excellent agreement with numerical energy band calculations for SrTiO3, KTaO3, ReO, and NaWO3.