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

摘要

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