Fluctuation-induced odd-frequency spin-triplet pairing in disordered electron liquid

TL;DR

This paper explores how disorder and magnetic fields in a 2D electron liquid can induce a novel odd-frequency spin-triplet pairing state, potentially explaining mysterious insulating phases in disordered superconductors.

Contribution

It introduces a mechanism for odd-frequency pairing induced by fluctuations in disordered conductors near a quantum critical point.

Findings

Identification of a quantum critical point separating superconducting and odd-frequency phases.

Proposal that odd-frequency pairing could explain insulating states in disordered superconducting films.

Analysis of fluctuation effects leading to effective interactions for unconventional pairing.

Abstract

We consider a two-dimensional disordered conductor in the regime when the superconducting phase is destroyed by the magnetic field. We analyze a combination of fluctuations of different origin which results in an effective interaction amplitude suitable for a spontaneous s-wave odd-frequency pairing instability. We observe that the end point of the superconductivity is a quantum critical point separating the conventional superconducting phase from a state with the odd-frequency spin-triplet pairing instability. We speculate that this could shed light on a rather mysterious insulating state observed in strongly disordered superconducting films in a broad region of the magnetic fields.