Proximity-induced time-reversal symmetry breaking at Josephson junctions between unconventional superconductors

TL;DR

This paper explores how Josephson junctions between unconventional superconductors can locally break time-reversal symmetry due to proximity effects, with implications for high-temperature superconductor experiments.

Contribution

It introduces the concept that proximity-induced order parameters can cause local time-reversal symmetry breaking at junctions of unconventional superconductors.

Findings

Proximity effects can induce time-reversal symmetry breaking states.

The phase structure of pairing wave functions is crucial for this effect.

Experimental signatures are discussed for high-temperature superconductors.

Abstract

We argue that a locally time-reversal symmetry breaking state can occur at Josephson junctions between unconventional superconductors. Order parameters induced by the proximity effect can combine with the bulk order parameter to form such a state. This property is specifically due to the intrinsic phase structure of the pairing wave function in unconventional superconductors. Experimental consequences of this effect in high-temperature superconductors are examined.