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.

arXiv comment15 pages, 13 figures

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Cited by in corpus (12)

• Two-Dimensional Homogeneous Fermi Gases
• Renormalization theory for the Fulde-Ferrell-Larkin-Ovchinnikov states at $T>0$
• A strongly interacting Sarma superfluid near orbital Feshbach resonances
• Dimensional crossover in a strongly interacting ultracold atomic Fermi gas
• Effective potential and quantum criticality for imbalanced Fermi mixtures
• Spin-imbalanced ultracold Fermi gases in a two-dimensional array of tubes
• Superfluidity in density imbalanced bilayers of dipolar fermions
• Two-dimensional Fermi gas in antiparallel magnetic fields
• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part II: Effects of population imbalance
• Trapped imbalanced fermionic superfluids in one dimension: A variational approach
• Two-dimensional imbalanced Fermi gas in antiparallel magnetic fields
• Novel dynamical excitations and roton-based measurement of Cooper-pair momentum in a two-dimensional Fulde-Ferrell-Larkin-Ovchinnikov superfluid on optical lattices