SURFACE ELECTRONIC-STRUCTURE OF COMPLEX B-METAL PEROVSKITES

We present photoemission results for two systems, SrSn1-xSbxO3 and its row 6 analogue, BaPb1-xBixO3. The variation in electronic structure a s a function of composition is explored, particularly in the region of the metal-to-nonmetal transitions. In the case of the Sr system, dram atic surface segregation of Sb is revealed. This is analogous to that observed in Sn1-xSbxO2. Resonant photoemission at oxygen and metal thr esholds is used to explore the character of the valence band and gap s tates in these materials.