Phase Diagram and Spectroscopy of FFLO states of two-dimensional d-wave superconductors

TL;DR

This paper models the phase diagram and local electronic properties of FFLO states in two-dimensional d-wave superconductors, providing theoretical predictions for experimental detection in materials like CeCoIn$_5$.

Contribution

It offers a self-consistent theoretical framework for understanding FFLO states in 2D d-wave superconductors, including phase transitions and spectroscopic signatures.

Findings

The transition from uniform to FFLO state is second order.

Predicted local density of states signatures observable via STM.

Phase diagram details for FFLO states in 2D d-wave superconductors.

Abstract

Experimental evidence suggests that the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state may be realized in the unconventional, heavy-fermion superconductor CeCoIn$_5$. We present a self-consistent calculation of the field versus temperature phase diagram and order parameter structures for the FFLO states of quasi-two-dimensional d-wave superconductors. We calculate the spatially nonuniform order parameter, free energy density, and local density of states for magnetic fields parallel to the superconducting planes. We predict that the lower critical magnetic field transition between the spatially uniform and nonuniform FFLO state is second order. We discuss the signatures of the nonuniform FFLO state which should be observable in scanning tunneling microscopy measurements of the local density of states.