Crossover in the local density of states of mesoscopic SNS junctions

TL;DR

This paper investigates the nonmonotonous crossover in the local density of states of mesoscopic SNS junctions caused by Andreev levels, highlighting its dependence on the normal metal bridge length and providing analytical insights.

Contribution

It presents analytical expressions and a detailed analysis of the crossover behavior in the local density of states of mesoscopic SNS junctions, focusing on the effects of Andreev levels.

Findings

Crossover in the local density of states vanishes at both the proximity and superconductive gaps.

Analytical expressions for the density of states at gap edges are derived.

The crossover is most pronounced when the normal metal bridge is shorter than the coherence length.

Abstract

Andreev levels deplete energy states above the superconductive gap, which leads to the peculiar nonmonotonous crossover in the local density of states of mesoscopic superconductor/normal-metal/superconductor junctions. This effect is especially pronounced in the case when the normal metal bridge length is small compared to the superconductive coherence length. Remarkable property of the crossover function is that it vanishes not only at the proximity induced gap but also at the superconductive gap. Analytical expressions for the density of states at the both gap edges, as well as general structure of the crossover are discussed.