Surface Electronic Structure of SrTiO₃ Studied by the DV-Xα Cluster Method

Abstract

The electronic structure of SrTiO₃ (100) surface is investigated by the DV-Xα cluster method. It is demonstrated by the first principle, calculations that the intrinsic deep surface states do not exist on this surface. On the other hand the possibility of the three types of shallow surface states is suggested; A) those derived from xz, yz like d orbitals of surface Ti, B) those coming from 3z²−r² like d orbital admixed with 4p_z, 4s orbitals of surface Ti, and C) those associated with the surface O 2p orbitals. The energy and properties of the localized electronic states induced by surface and bulk oxygen vacancies are calculated and compared with recent UPS and ELS experiments.