Superfluidity of a dipolar Fermi gas in 2D optical lattices bilayer

Abstract

We propose a model for addressing the superfluidity of two different Fermi species confined in a bilayer geometry of square optical lattices. The fermions are assumed to be molecules with interlayer s-wave interactions, whose dipole moments are oriented perpendicularly to the layers. Using functional integral techniques we investigate the BCS-like state induced in the bilayer at finite temperatures. In particular, we determine the critical temperature as a function of the coupling strength between molecules in different layers and of the interlayer spacing. By means of Ginzburg-Landau theory we calculate the superfluid density. We also study the dimerized BEC phase through the Berezinskii-Kosterlitz-Thouless transition, where the effective mass leads to identify the crossover from BCS to BEC regimes. The possibility of tuning the effective mass as a direct consequence of the lattice confinement, allows us to suggest a range of values of the interlayer spacing, which would enable observing this superfluidity within current experimental conditions.