Phonon-Drag Thermopower Correlations To T-C In Superconducting Srxnd1-Xcuo2-Delta - Evidence For Phonon-Mediated Pairing In The High-T-C Parent Compounds

The ACuO(2) compounds-containing only CuO2 planes separated by A ions-are the basic ''building blocks'' of the more complex high-T-c superconductors. Trivalently doped SrxNd1-xCuO2-delta thin films are shown to superconduct with the appearance of a phonon-drag contribution to the thermopower at the superconducting doping threshold. A monotonic increase in this phonon-drag contribution with Te suggests that electron-phonon interactions play an important role in the pairing mechanism. A correlation between the deduced BCS coupling constants and T-c is consistent with strong-coupling theory.