Enhanced Josephson tunneling between high-temperature superconductors through a normal pseudogap underdoped cuprate with a finite-energy cooperon

Kun Huang^1(a), Wei-Qiang Chen^2,1, T. M. Rice^3,1,4 and F. C. Zhang¹

¹ Department of Physics, and Center of Theoretical and Computational Physics, The University of Hong Kong Hong Kong, China
² Department of Physics, South University of Science and Technology of China - Shenzhen, Guangdong, China
³ Institut für Theoretische Physik, ETH Zürich - CH-8093 Zürich, Switzerland
⁴ Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory Upton, NY 11973, USA

^(a) kunhuang09@gmail.com

Received: 22 June 2012
Accepted: 5 July 2012

Abstract

The Josephson coupling between optimally cuprate superconductors separated by a spacer with a finite-energy cooperon excitation, which contributes to the Josephson coupling strength, is examined. For an underdoped-cuprate barrier in its normal state, the YRZ model gives a good description of the temperature-dependent enhanced Josephson coupling. A detailed examination of the origin of the enhancement shows a significant contribution from the cooperon excitation which is comparable to that from nodal quasiparticles.