Giant proximity effect in a phase-fluctuating superconductor

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.

4 pages, 3 figures; version to appear in PRL (results of simulations in 3d added). For related work and info visit http://www.physics.ubc.ca/~franz