ELECTRONIC-STRUCTURE OF (K,BA)BIO3 CRYSTALS

Measured on crystalline surfaces free of inter-grain contribution, the intrinsic electronic structures of superconducting K-substituted bari um bismuthates show only single barium, bismuth and oxygen lines, acco rding to the absence of disproportionnation. Potassium core level line exhibits two independent components, reflecting either the possibilit y of two substitutional sites or the evidence of a potassium segregati on.