Broken Time-reversal Symmetry in Josephson Junction with an Anderson impurity and multi band superconductors

TL;DR

This paper investigates how strong correlations in a Josephson junction with an Anderson impurity and multi-band superconductors can induce a time-reversal symmetry breaking ground state, revealing fundamental effects of correlations.

Contribution

It demonstrates that strong correlations can drive a Josephson junction into a time-reversal symmetry breaking state near local moment formation, a novel insight into correlated superconducting systems.

Findings

Time-reversal symmetry breaking occurs when inter-band coupling exceeds a threshold.

Impurity magnetization is reduced in the time-reversal breaking phase.

The critical regime aligns with local moment formation.

Abstract

A Josephson junction consisting of an Anderson impurity weakly coupled with two-band and single-band superconductors exposes a time reversal breaking ground state when the coupling between the two bands exceeds a certain threshold. The critical regime occurs around local moment formation. This indicates a fundamental and distinct role of strong correlations: Driving a system into a time reversal breaking ground state. One of the observable consequences is that the impurity magnetization in this phase is reduced.