# Vortex state in a Fulde-Ferrell-Larkin-Ovchinnikov superconductor based on the quasiclassical theory

## TL;DR

This paper models the vortex state in FFLO superconductors, specifically CeCoIn_5, using quasiclassical theory to analyze the structure of pair potentials, magnetic fields, and electronic states, highlighting signatures for experimental detection.

## Contribution

It provides a detailed three-dimensional theoretical analysis of FFLO vortex states with comparisons between s-wave and d-wave pairings, including potential experimental signatures.

## Key findings

- Sharp peak states in local density of states at FFLO nodal planes and vortex cores.
- Enhanced local paramagnetic moments due to c-phase shift.
- Discussion of NMR and neutron scattering as detection methods.

## Abstract

We investigate the vortex state with Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) modulations suggested for a high field phase of CeCoIn_5. On the basis of the quasiclassical Eilenberger theory, we calculate the three dimensional structure of pair potentials, internal magnetic fields, paramagnetic moments, and electronic states, for the s-wave and the d-wave pairings comparatively. The \pi-phase shift of the pair potential at the FFLO nodal plane or at the vortex core induces sharp peak states in the local density of states, and enhances the local paramagnetic moment. We also discuss the NMR spectrum and the neutron scattering as methods to detect the FFLO structure.