ELECTRON-PHONON CONTRIBUTION TO THERMOPOWER IN SI-DOPED SUPERCONDUCTING BI COMPOUNDS

Resistivity p and thermoelectric power S as a function of temperature on samples of nominal composition (Bi0.8Pb0.2)(2)Sr2Ca3(Cu1-xSix)(4)O1 2-delta, for different x values at small concentrations, have been car ried out. We find a correlation between p and an enhancement in S obse rved above T-c. We analyze the results in terms of conventional theore tical models that include vertex and other electron-phonon (e-p) corre ctions to the scattering due to impurities. It is argued that in the c opper oxides the e-p effects, usually negligible in normal metals at t emperatures small compared to the Debye temperature, might be signific ant near and above T-c. A small contribution due to the phonon drag ef fect is also discussed. It is suggested that the trends of our results adjust to the predictions of those conventional models.