CALCULATION OF ELECTRONIC STATES IN PEROVSKITE-TYPE OXIDE BY THE DV-X-ALPHA METHOD - THE EFFECTS OF OXYGEN DEFECTS

The effects of oxygen defects on the electronic states in the perovski te-type oxide, SrCoO3-delta, were investigated by the DV-X alpha molec ular orbital method. The oxygen-defect model was constructed on the ba sis of the brownmillerite-type structure. We calculated four kinds of cluster models, corresponding to delta = 0, 1/6, 1/3, and 1/2, The cal culated energy of O1s state in SrCoO3-delta Splits into two levels wit h the energy difference of 2 eV, which is consistent with the experime nted results in La1-xSrxCoO3-delta by X-ray photoelectron spectroscopy . (C) 1995 Academic Press, Inc.