Theory of Josephson effect in chiral p-wave superconductor / diffusive normal metal / chiral p-wave superconductor junctions

TL;DR

This paper investigates the Josephson effect in chiral p-wave superconductor/diffusive normal metal junctions, revealing the induced odd-frequency triplet pairing and conventional Josephson current behavior, with implications for understanding Sr2RuO4.

Contribution

It provides a theoretical analysis of Josephson effects in chiral p-wave superconductor junctions, highlighting the odd-frequency pairing and the conditions for 0-pi transitions.

Findings

Induced Cooper pairs in DN have odd-frequency spin-triplet s-wave symmetry.

Josephson current exhibits a sinusoidal phase relation and decays exponentially with junction length.

0-pi transition can be achieved by varying temperature or junction length.

Abstract

We study the Josephson effect between chiral p-wave superconductor / diffusive normal metal (DN) / chiral p-wave superconductor (CP/DN/CP) junctions using quasiclassical Green's function formalism with proper boundary conditions. The px+ipy-wave symmetry of superconducting order parameter is chosen which is believed to be a pairing state in Sr2RuO4. It is shown that the Cooper pairs induced in DN have an odd-frequency spin-triplet s-wave symmetry, where pair amplitude is an odd function of Matsubara frequency. Despite the peculiar symmetry properties of the Cooper pairs, the behavior of the Josephson current is rather conventional. We have found that the current phase relation is almost sinusoidal and the Josephson current is proportional to exp(-L/xi), where xi is the coherence length of the Cooper pair in DN and L is the length of DN. The Josephson current between CP / diffusive ferromagnet metal (DF) / CP junctions is also calculated. It is shown that the 0-pi transition can be realized by varying temperature or junction length L similar to the case of conventional s-wave junctions. These results may serve as a guide to study superconducting state of Sr2RuO4.