FORMATION OF LOCALIZED HOLE STATES IN COMPLEX OXIDES .1. HOLE STATES IN BATIO3

Defect electrons (holes) play an important role in most technologicall y important complex oxides. In this contribution we present the first detailed characterization of localized hole states in such materials. Our investigations employ advanced embedded-cluster calculations which consistently include electron correlations and defect-induced lattice relaxations. This is necessary in order to account for the variety of possible hole-state manifestations. Even in highly ionic oxides such as MgO, there exists a delicate interplay between electron correlation s and defect-induced lattice deformations.