Publication : t19/166

Abstract:
We recover here the formation of Andreev bound states in SNS junctions by modeling an NS junction as a delta-function "Andreev" impurity, i.e., a localized potential which scatters an electron into a hole with opposite spin. We show using the scattering matrix formalism that, quite surprisingly, an "Andreev" impurity is equivalent to an NS junction characterized by both Andreev reflection and a finite amount of normal scattering. Our formalism cannot capture ideal NS junctions, but only imperfect ones, however, we show that this is enough to capture the generic features of Andreev bound states. Thus, we provide a new analytical tool to describe the formation of ABS using the T-matrix formalism, valid for imperfect junctions which can in general be described only by numerical tools.

publi.pdf