The Gor'kov and Melik-Barkhudarov correction to the mean-field critical field transition to Fulde-Ferrell-Larkin-Ovchinnikov states

TL;DR

This paper investigates how induced interactions affect the critical magnetic field for FFLO state formation in imbalanced Fermi gases, revealing significant suppression and potential destruction of FFLO states due to impurities.

Contribution

It provides a detailed calculation of the Gor'kov and Melik-Barkhudarov correction to the critical field for FFLO states at zero temperature, considering both clean and dirty systems.

Findings

Critical field is strongly suppressed in imbalanced Fermi gases.

Impurities can completely destroy the FFLO state.

Phase space for FFLO stability is significantly reduced.

Abstract

The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, characterized by Cooper pairs condensed at finite-momentum are, at the same time, exotic and elusive. It is partially due to the fact that the FFLO states allow superconductivity to survive even in strong magnetic fields at the mean-field level. The effects of induced interactions at zero temperature are calculated in both clean and dirty cases, and it is found that the critical field at which the quantum phase transition to an FFLO state occurs at the mean-field level is strongly suppressed in imbalanced Fermi gases. This strongly shrinks the phase space region where the FFLO state is unstable and more exotic ground state is to be found. In the presence of high level impurities, this shrinkage may destroy the FFLO state completely.