Flow-Induced Charge Modulation in Superfluid Atomic Fermions Loaded into an Optical Kagome Lattice

Abstract

We study the superfluid state of atomic fermions in a tunable optical kagome lattice motivated by recent experiments. We show that imposed superflow induces spatial modulations in the density and order parameter of the pair condensate and leads to a charge modulated superfluid state analogous to a supersolid state. The spatial modulations in the superfluid emerge due to the geometric effect of the kagome lattice that introduces anisotropy in hopping amplitudes of fermion pairs in the presence of superflow. We also study superflow instabilities and find that the critical current limited by the dynamical instability is quite enhanced due to the large density of states associated with the flatband. The charge modulated superfluid state can sustain high temperatures close to the transition temperature that is also enhanced due to the flatband, and is therefore realizable in experiments.

4+3 pages, 5 figures

References in corpus (10)

• Many-Body Physics with Ultracold Gases
• High temperature fractional quantum Hall states
• Bose condensation in flat bands
• Observation of a two-dimensional Fermi gas of atoms
• Critical velocity for superfluid flow across the BEC-BCS crossover
• BCS-BEC crossover on the two-dimensional honeycomb lattice
• Ultracold Fermions in a Graphene-Type Optical Lattice
• Phase diagram for a Bose-Einstein condensate moving in an optical lattice
• Collective modes and superflow instabilities of strongly correlated Fermi superfluids
• Stability of Superflow for Ultracold Fermions in Optical Lattices