Proximity Effect in Presence of Quantum Fluctuations

Abstract

The effect of Coulomb interaction upon superconductive proximity effect in disordered metals is studied, employing newly developed Keldysh functional approach (cond-mat/9907358). We have calculated subgap Andreev conductance between superconductor and 2D dirty film, as well as Josephson coupling via such a film. Both two qualitatively different Coulomb effects - suppression of the tunneling density of states and disorder-enchanced repulsion in the Cooper channel - are shown to be important at sufficiently low temperatures.