Fermi-liquid effects in the Fulde-Ferrell-Larkin-Ovchinnikov state of two-dimensional d-wave superconductors

TL;DR

This paper investigates how Fermi-liquid interactions influence the phase diagram and stability of the FFLO state in two-dimensional d-wave superconductors under magnetic fields, revealing effects on phase transitions and susceptibility.

Contribution

It introduces a detailed analysis of Fermi-liquid effects on the FFLO state in 2D d-wave superconductors, including phase transition characteristics and implications for materials like CeCoIn$_5$.

Findings

Decreasing Fermi-liquid parameter $F_0^a$ increases spin susceptibility.

Negative $F_0^a$ induces a first-order transition from normal to superconducting state.

Fermi-liquid interactions significantly modify the FFLO phase stability.

Abstract

We study the effects of Fermi-liquid interactions on quasi-two-dimensional d-wave superconductors in a magnetic field. The phase diagram of the superconducting state, including the periodic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in high magnetic fields, is discussed for different strengths of quasiparticle many-body interactions within Landau's theory of Fermi liquids. Decreasing the Fermi-liquid parameter $F_0^a$ causes the magnetic spin susceptibility to increase, which in turn leads to a reduction of the FFLO phase. It is shown that a negative $F_0^a$ results in a first-order phase transition from the normal to the uniform superconducting state in a finite temperature interval. Finally, we discuss the thermodynamic implications of a first-order phase transition for CeCoIn$_5$.