Larkin-Ovchinnikov superfluidity in a two-dimensional imbalanced atomic Fermi gas

Abstract

We present an extensive study of two-dimensional Larkin-Ovchinnikov (LO) superfluidity in a spin-imbalanced two-component atomic Fermi gas. In the context of Fulde-Ferrell-Larkin- Ovchinnikov (FFLO) phase, we explore a wide and generic class of pairing gap functions with ex- plicit spatial dependency. The mean-field theory of such phases is applied through the Bogoliubov-de Gennes equations in which the pairing gap can be determined self-consistently. In order to systemat- ically explore the configuration space we consider both the canonical and grand canonical ensembles where we control the polarization or chemical potentials of the system, respectively. The mean-field calculations enable us to understand the nature of the phase transitions in the fully paired Bardeen- Cooper-Schrieffer (BCS) state, exotic LO phase, and partially polarized free Fermi gas. The order of the phase transitions has been examined and in particular we find a weak first-order phase transition between the exotic inhomogeneous LO phase and the BCS phase. In comparison to the three-dimensional case, where the phase diagram is dominated by a generic separation phase, we predict a broader parameter space for the spatially inhomogeneous LO phase. By computing the superfluid density of the LO phase at different polarization, we show how the superfluidity of the system is suppressed with increasing spin polarization.

15 pages, 13 figures

References in corpus (18)

• Observation of Phase Separation in a Strongly-Interacting Imbalanced Fermi Gas
• Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
• Calorimetric Evidence for a Fulde-Ferrell-Larkin-Ovchinnikov Superconducting State in the Layered Organic Superconductor κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$
• Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas
• Evidence of Andreev bound states as a hallmark of the FFLO phase in $\kappa$-(BEDT-TTF)${}_2$Cu(NCS)${}_2$
• A Unitary Fermi Supersolid: The Larkin-Ovchinnikov Phase
• Unconventional superfluid in a two-dimensional Fermi gas with anisotropic spin-orbit coupling and Zeeman fields
• Pairing fluctuations and the superfluid density through the BCS-BEC crossover
• Finite temperature phase diagram of a polarized Fermi gas in an optical lattice
• Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
• Larkin-Ovchinnikov state in resonant Fermi gas
• FFLO state in 1, 2, and 3 dimensional optical lattices combined with a non-uniform background potential
• Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases with population and mass imbalance
• Mean field thermodynamics of a spin-polarized spherically trapped Fermi gas at unitarity
• Radio frequency spectroscopy of a strongly imbalanced Feshbach-resonant Fermi gas
• Stable Fulde-Ferrell-Larkin-Ovchinnikov pairing states in 2D and 3D optical lattices
• Superfluid density and Berezinskii-Kosterlitz-Thouless transition of a spin-orbit coupled Fulde-Ferrell superfluid
• The Josephson relation for the superfluid density in the BCS-BEC crossover

Cited by in corpus (2)

• Renormalization theory for the Fulde-Ferrell-Larkin-Ovchinnikov states at $T>0$
• Spin-imbalanced ultracold Fermi gases in a two-dimensional array of tubes