Momentum space imaging of the FFLO state

Abstract

In a magnetic field superconductors (SC) with small orbital effect exhibit the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase above the Pauli limiting field. It is characterized by Cooper pairs with finite center of mass momentum and is stabilized by the gain in Zeeman energy of depaired electrons in the imbalanced Fermi gas. The ground state is a coherent superposition of paired and depaired states. This concept, although central to the FFLO state lacks a direct experimental confirmation. We propose that STM quasiparticle interference (QPI) can give a direct momentum space image of the depaired states in the FFLO wave function. For a proof of principle we investigate a 2D single orbital tight binding model with a SC s-wave order parameter. Using the equilibrium values of pair momentum and SC gap we calculate the spectral function of quasiparticles and associated QPI spectrum as function of magnetic field. We show that the characteristic depaired Fermi surface parts appear as a fingerprint in the QPI spectrum of the FFLO phase and we demonstrate its evolution with field strength. Its observation in STM experiments would constitute a direct proof for FFLO ground state wave function.

17 pages, 8 figures

References in corpus (11)

• Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion Superconductors
• Detection of a Cooper-Pair Density Wave in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$
• Calorimetric Evidence for a Fulde-Ferrell-Larkin-Ovchinnikov Superconducting State in the Layered Organic Superconductor κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$
• BEC-BCS crossover, phase transitions and phase separation in polarized resonantly-paired superfluids
• Evidence of Andreev bound states as a hallmark of the FFLO phase in $\kappa$-(BEDT-TTF)${}_2$Cu(NCS)${}_2$
• Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi two-dimensional CeCoIn5
• Phase Diagram and Spectroscopy of FFLO states of two-dimensional d-wave superconductors
• Switching of magnetic domains reveals evidence for spatially inhomogeneous superconductivity
• Impurity-induced configuration-transition in the Fulde-Ferrell-Larkin-Ovchinnikov state of a d-wave superconductor
• Larkin-Ovchinnikov phases in two-dimensional square lattices
• Multi-orbital Fulde-Ferrell-Larkin-Ovchinnikov State in SrTiO_3 Heterostructures

Cited by in corpus (6)

• Amperean Pairing at the Surface of Topological Insulators
• Fermi surface segmentation in the helical state of a Rashba superconductor
• Fulde-Ferrell-Larkin-Ovchinnikov state in strongly correlated d-wave superconductors
• Dynamical magnetic response in superconductors with finite momentum pairs
• Image of helical local moment magnetic order in the STM spectrum
• Magnetic excitations in the helical Rashba superconductor