Giant proximity effect in a phase-fluctuating superconductor

TL;DR

This paper reveals a giant proximity effect in phase-fluctuating superconductors, where a normal barrier made of the same material enhances Josephson coupling, explaining recent experimental observations in cuprates.

Contribution

It introduces a novel proximity effect mechanism in phase-fluctuating superconductors supported by theoretical and numerical evidence.

Findings

Giant enhancement of Josephson effect observed

Proximity effect explained by phase fluctuations

Potential explanation for experimental cuprate results

Abstract

When a tunneling barrier between two superconductors is formed by a normal material that would be a superconductor in the absence of phase fluctuations, the resulting Josephson effect can undergo an enormous enhancement. We establish this novel proximity effect by a general argument as well as a numerical simulation and argue that it may underlie recent experimental observations of the giant proximity effect between two cuprate superconductors separated by a barrier made of the same material rendered normal by severe underdoping.