Josephson interferometer in a ring topology as a symmetry prove of Sr_2RuO_4

TL;DR

This paper theoretically investigates Josephson interferometers with Sr2RuO4, revealing how pairing symmetry affects critical current responses to magnetic fields, and explaining recent experimental observations.

Contribution

It introduces a theoretical analysis of Josephson effects in SQUIDs with Sr2RuO4, highlighting the impact of pairing symmetry and chiral domains on critical current behavior.

Findings

Critical current asymmetry in corner SQUIDs near critical temperatures.

Dependence of Josephson response on pairing symmetry and magnetic field.

Explanation of recent experimental results on Sr2RuO4 Josephson effects.

Abstract

The Josephson effect is theoretically studied in two types of SQUIDs consisting of $s$ wave superconductor and Sr$_2$RuO$_4$. Results show various response of the critical Josephson current to applied magnetic fields depending on the type of SQUID and on the pairing symmetries. In the case of a $p_x+ip_y$ wave symmetry, the critical current in a corner SQUID becomes an asymmetric function of magnetic fields near the critical temperatures. Our results well explain a recent experimental finding [Nelson et. al, Science \textbf{306}, 1151 (2004)]. We also discuss effects of chiral domains on the critical current.