Superconducting Diode Effect in Multiphase Superconductors

TL;DR

This paper reveals a new intrinsic mechanism for the superconducting diode effect in multiphase superconductors, showing high diode efficiencies without relying on parity mixing, and suggests relevance to materials like UTe$_2$.

Contribution

It introduces a novel mechanism for the superconducting diode effect in multiphase superconductors that does not depend on parity mixing, supported by Ginzburg-Landau and microscopic models.

Findings

Phase transitions into a mixed phase with finite-momentum Cooper pairs exhibit high diode efficiencies.

Parity mixing is not essential for the superconducting diode effect.

The mechanism may apply to known multiphase superconductors such as UTe$_2$.

Abstract

We identify a new mechanism for the intrinsic superconducting diode effect (SDE) in multiphase superconductors. Using a Ginzburg-Landau and a microscopic two-band model, we find phase transitions into a mixed phase with finite-momentum Cooper pairs and SDE with high (including maximal) diode efficiencies, despite the individual phases exhibiting no SDE and equal inversion parity. We thus show that parity mixing $-$ invoked in previous proposals $-$ is not a crucial ingredient for SDE. The new mechanism may be relevant in a multitude of known multiphase superconductors like UTe$_2$.