Charge transport across a mesoscopic superconductor-normal metal junction:coherence and decoherence effects

We present a simple scattering approach to the charge transport across a re alistic superconductor-normal injector interface of a finite transmittance that is modeled by a double-barrier mesoscopic junction. For a d-wave pairi ng symmetry, our calculations combine a fully quantum-mechanical scattering formalism with a self-consistent estimation of Andreev reflection coeffici ents within the quasi-classical Eilenberger equation scheme for a free spec ular superconducting surface. Numerical simulations confirm experimental cr iteria of Cucolo, for the unconventional superconducting origin of conducta nce anomalies in high-temperature oxides. A discussion of dephasing effects caused by inelastic scattering processes in the interlayer and their impac t on the conductance spectra is given. (C) 2001 Published by Elsevier Scien ce B.V.