Reproducibility of Phonon Structures in the Tunneling Conductance of Bi2-xPbxSr2Ca2Cu3O10-y

Abstract
Phonon structures appeared in the tunneling conductance of a Bi2-x Pb x Sr2Ca2Cu3O10-y -GaAs junction. They are similar to the previous structures obtained for SnO2 junctions. There is no large structure other than that of the phonon in a single phonon frequency range. Above that range, tiny peaks appeared up to 180 meV, which may be anharmonic phonon structures. From the phonon positions, 2Δ is determined to be 60±4 meV and from the temperature of disappearance, T c is estimated to be 95±6 K. Thus, 2Δ/k B T c is 7.3±1.0.