Disordered Fulde-Ferrel-Larkin-Ovchinnikov State in d-wave Superconductors

TL;DR

This paper investigates the effects of disorder on the FFLO superconducting state in d-wave superconductors, revealing the potential for an 'FFLO glass' state and analyzing magnetic properties relevant to experimental observations.

Contribution

It introduces the concept of an 'FFLO glass' state induced by strong point disorder and analyzes the spatial and magnetic properties of disordered FFLO states in d-wave superconductors.

Findings

Disorder affects the spatial structure of the FFLO state.

Strong point disorder can lead to an 'FFLO glass' state.

The local spin susceptibility distribution relates to FFLO nodal planes.

Abstract

We study the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) superconducting state in the disordered systems. We analyze the microscopic model, in which the d-wave superconductivity is stabilized near the antiferromagnetic quantum critical point, and investigate two kinds of disorder, namely, box disorder and point disorder, on the basis of the Bogoliubov-deGennes (BdG) equation. The spatial structure of modulated superconducting order parameter and the magnetic properties in the disordered FFLO state are investigated. We point out the possibility of "FFLO glass" state in the presence of strong point disorders, which arises from the configurational degree of freedom of FFLO nodal plane. The distribution function of local spin susceptibility is calculated and its relation to the FFLO nodal plane is clarified. We discuss the NMR measurements for CeCoIn_5.