Electrical Conductivity of the Oxide Superconductor Ba_0.58K_0.42BiO_2.96

Abstract

Mechanism of electrical conductivity in the normal state of the perovskite-type oxide superconductor Ba_0.58K_0.42BiO_2.96 has been investigated by measuring the conductivity and the Hall coefficient in the temperature range of 20--300, K, using a single crystal which seems to exhibit the intrinsic feature of conductivity because of the small residual resistivity value of 1× 10^-4, Ω · cm. The best analytical fit of temperature dependence of resistivity is obtained assuming scattering of the electron by both the acoustic phonon with the Debye temperature of 320, K and the optical phonons with the Einstein temperatures of 835, K and 460, K. The small value of the Hall mobility of about 2, cm²/V· s at room temperature means strong interaction of electrons with phonons. We emphasize the important role of electron-LO phonon interaction in the mechanism of conductivity.