Reentrant Superconductivity from Competing Spin-Triplet Instabilities

TL;DR

This paper demonstrates that reentrant superconductivity can occur due to competing spin-triplet channels in strong magnetic fields, challenging traditional views on magnetic suppression of superconductivity.

Contribution

It introduces a minimal Ginzburg--Landau model with two coupled spin-triplet order parameters to explain reentrant superconductivity from competing instabilities.

Findings

Reentrant superconductivity arises from competition between spin-unpolarized and spin-polarized channels.

Magnetic fields can reorganize the hierarchy of superconducting instabilities.

Reentrant instability curves are demonstrated over a broad parameter range.

Abstract

Reentrant superconductivity in strong magnetic fields challenges the conventional expectation that magnetic fields necessarily suppress superconductivity. We show that reentrant superconducting instability can arise from the competition between spin-unpolarized and spin-polarized superconducting channels. Using a minimal Ginzburg--Landau theory with two coupled spin-triplet order parameters, we demonstrate that a magnetic field can reorganize the hierarchy of superconducting instabilities, yielding a characteristic reentrant instability curve over a broad parameter range.