Magnetic field induced singlet - triplet phase transition in quasi one-dimensional organic superconductors

TL;DR

This paper presents a theoretical model predicting a magnetic field-induced transition from singlet to triplet superconducting phases in quasi-one-dimensional organic superconductors, aligning with recent experimental observations.

Contribution

It introduces a mean field model showing a first order singlet-triplet phase transition under magnetic fields, explaining recent experimental data in (TMTSF)2ClO4.

Findings

Predicted a first order phase transition at a few teslas.

Identified a change from singlet to triplet pairing symmetry.

Aligned theoretical results with recent experimental data.

Abstract

We propose a theoretical model of quasi-one-dimensional superconductors, with attractive electron-electron interactions dominant in the singlet d-wave channel and sub-dominant in the p-wave channel. We discuss, in the mean field approximation, the effect of a magnetic field applied perpendicularly to the direction of the lowest conductivity. The lowest free energy phase corresponds to a singlet d-wave symmetry in low fields, but to a triplet symmetry in high fields. A first order singlet-triplet phase transition is expected at moderate applied fields of a few teslas. We propose to ascribe the recent critical field and NMR experimental data, observed in superconducting (TMTSF)2ClO4 to such an effect.