High T sub c Superconductivity in Bismuthates - How Many Roads Lead to High T sub c?.

The superconducting transition temperature in BaBiO sub 3 based superconductors exceeds 30K. Magnetic measurements are analyzed to give their density of states at E sub F, N*(0) proportional to gamma. The uniqueness of Bi-O and Cu-O superconductors is revealed in an updated T sub c -gamma plot. The two classes of compounds share basic electronic properties, particularly a partially unoccuppied band with significant O2p character, which might favor a common pairing mechanism.