EXPLANATION OF THE TEMPERATURE-DEPENDENCE OF RESISTIVITY IN HIGH-T(C)SUPERCONDUCTING BA0.6K0.4BIO3 BY ELECTRON-PHONON SCATTERING

The resistivity rho(T) of single crystals of the cubic high-T(c) super conductor Ba0.6K0.4BiO3 with T(c) = 30 K has been measured in the temp erature range from 4.2 to 300 K. The experimental curve is well approx imated in the framework of the classical electron-phonon model of resi stivity by the Gruneisen type dependence using the phonon spectrum in the form of an acoustic branch and a widely separated narrow optical p eak. Characteristic temperatures of the phonon spectrum - the Debye te mperature I(D) of the acoustic branch and the Einstein temperature I(E ) of the optical mode - and the ratio of contributions of acoustic and optical phonons to the resistivity were derived from the best fit of the theoretical curve rho(T) to the experimental one. The optical phon ons of the oxygen breathing mode give a relatively larger contribution to the resistivity. Correspondingly, the contribution of optical phon ons to the constant of electron-phonon interaction lambda is larger co mpared to the contribution of acoustic phonons.