TEMPERATURE-DEPENDENCE OF THE TUNNELING CONDUCTANCE OF BI2SR2CACU2O8 - PHONON CONTRIBUTION TO HIGH-T-C SUPERCONDUCTIVITY

Temperature dependence of the tunneling conductance of a Bi2Sr2CaCu2O8 -GaAs junction was investigated both experimentally and theoretically. The spectral function deduced from the experimental result at 4.2 K i s applied to the Eliashberg equations at higher temperatures. The theo ry well explains the observed smearing of the phonon structures, but t here is a small discrepancy between the experimental and the theoretic al gap and the former decreases more rapidly than the latter as temper ature increases.