Superconductivity in BaPb1-xBixO3and BaxK1-xBiO3

Abstract
The superconducting transition temperatures of BaPb1-xBixO3 (BPB) and BaxK1-xBiO3 (BKB) are evaluated on the basis of the strong-coupling theory. The electron-lattice interaction is calculated microscopically by using the realistic electronic band structure. It is shown that the superconducting properties of BKB, such as high transition temperatures ( approximately=30 K) and rather small isotope effects, can be understood within the phonon mechanism.