Spontaneous finite momentum pairing in superconductors without inversion symmetry

TL;DR

This paper explores how magnetic fluctuations in non-centrosymmetric superconductors induce a transition to a finite momentum pairing state, which can generate persistent currents and is influenced by magnetic fields.

Contribution

It reveals a novel phase transition driven by magnetic fluctuations leading to finite momentum pairing in superconductors without inversion symmetry.

Findings

Transition to finite momentum pairing state driven by magnetic fluctuations

Existence of persistent currents without magnetic field in certain geometries

Transition temperature can be increased by applying a Zeeman magnetic field

Abstract

We analyze the effect of magnetic fluctuations in superconductors with strong spin-orbit coupling and show that they drive a phase transition between two superconducting states: a conventional phase with zero center-of-mass momentum of Cooper pairs, and an exotic phase with non-zero pair momentum. The latter is found to exhibit persistent currents without magnetic field in doubly connected geometries such as rings. Surprisingly, the transition temperature into the superconducting state can be increased by applying a Zeeman magnetic field.