Local density of states and self-consistent gap function in clean mesoscopic SNSNS systems

Abstract

A multiple-scattering Green's function formalism is used to calculate exactly and in Andreev approximation (AA) the local density of states (LDOS) in a clean mesoscopic SNSNS junction. Comparison of the LDOS in SNS and SNSNS junctions shows that the Andreev-bound state energies in the latter are shifted relative to those in the former. The magnitude of the energy shift is determined by the height of the gap in the middle superconducting electrode and the coherence length of the superconductor. LDOS peaks typical of Andreev states are also observed in the superconducting parts. In addition, self-consistent calculation of the gap function exhibits various features of the proximity effect.