Influence of the domain walls on the Josephson effect in Sr$_2$RuO$_4$

TL;DR

This paper provides a theoretical analysis of how domain walls in Sr$_2$RuO$_4$ influence the Josephson effect, explaining experimental deviations in interference patterns and hysteresis through a Ginzburg-Landau model.

Contribution

It introduces a Ginzburg-Landau theoretical framework to interpret the impact of domain walls on Josephson interference in Sr$_2$RuO$_4$, aligning with experimental observations.

Findings

Deviations in Fraunhofer patterns explained by domain wall effects

Hysteresis phenomena accounted for by the model

Anisotropy and orientation are key to domain wall structure

Abstract

A detailed theoretical interpretation of the Josephson interference experiment between Sr$_2$RuO$_4$ and Pb reported by Kidwingira \textit{et al} is given. Assuming chiral p-wave pairing symmetry a Ginzburg-Landau theory is derived in order to investigate the structure of domain walls between chiral domains. It turns out that anisotropy effects of the Fermi surface and the orientation of the domain walls are essential for their internal structure. Introducing a simple model for a Josephson junction the effect of domain walls intersecting the interface between Sr$_2$RuO$_4$ and Pb is discussed. It is shown that characteristic deviations of the Fraunhofer interference pattern for the critical Josephson current as a function of the magnetic field occurs in qualitative agreement with the experimental finding. Moreover the model is able also to account for peculiar hysteresis effects observed in the experiment.