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 superco nductors. 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 incr ease in this phonon-drag contribution with Te suggests that electron-p honon interactions play an important role in the pairing mechanism. A correlation between the deduced BCS coupling constants and T-c is cons istent with strong-coupling theory.