Probing Pair Density Waves with Twisted Josephson Junctions

TL;DR

This paper proposes using twisted Josephson junctions as a phase-sensitive method to detect and characterize pair density waves in superconductors, with specific signatures observable under magnetic fields.

Contribution

It introduces a novel approach leveraging twisted interfaces and magnetic fields to identify PDWs, providing a robust and adaptable detection method.

Findings

Critical Josephson current peaks at finite magnetic field depending on twist angle and PDW period

Method distinguishes pure PDW from coexisting charge or spin density waves

Results are robust against junction geometry variations and disorder

Abstract

We show that twisted interfaces between superconductors can serve as a phase-sensitive platform for the detection and characterization of pair density waves (PDW). In the presence of an in-plane magnetic field, the critical Josephson current of a twisted PDW interface is maximal at a finite field value, determined by the twist angle and the PDW period -- an explicit signature of the PDW. The results are robust to variations in junction geometry and can be adapted to certain cases with strong disorder or fluctuations. Their temperature dependence allows to distinguish pure PDW from byproducts of coexistence of superconductivity and charge- or spin- density waves.