Functional superconductor interfaces from broken time-reversal symmetry

TL;DR

This paper predicts that breaking time-reversal symmetry in triplet superconductor Josephson junctions induces magnetic instability and fractional flux quanta, revealing a new exotic Josephson state with observable signatures.

Contribution

It introduces a novel theoretical framework linking broken time-reversal symmetry to magnetic instability and fractional flux states in superconductor interfaces.

Findings

Magnetic instability occurs at the tunneling barrier.

Fractional flux quanta are predicted at the junction.

Critical current signatures indicate the instability.

Abstract

The breaking of time-reversal symmetry in a triplet superconductor Josephson junction is shown to cause a magnetic instability of the tunneling barrier. Using a Ginzburg-Landau analysis of the free energy, we predict that this novel functional behaviour reflects the formation of an exotic Josephson state, distinguished by the existence of fractional flux quanta at the barrier. The crucial role of the orbital pairing state is demonstrated by studying complementary microscopic models of the junction. Signatures of the magnetic instability are found in the critical current of the junction.