Larkin-Ovchinnikov phases in two-dimensional square lattices

Abstract

We consider a two-component gas of fermions in optical lattices in the presence of a population imbalance within a mean-field theory. We study phase transitions from a normal gas of unpaired fermions to a superfluid phase of Bose-condensed Cooper pairs. The possibility of Cooper pairs with a nonzero center-of-mass momentum is included, which corresponds to a so-called Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state. We find that for population imbalanced systems such states can form the ground state. The FF and LO state are compared and it is shown that actually the LO state is energetically more favorable. We complete the mean-field phase diagram for the LO phase and show that it is qualitatively in excellent agreement with recent diagrammatic Monte Carlo calculations. Subsequently, we calculate the atomic density modulations in the LO phase.

arXiv comment11 pages, 7 figures, submitted to Journal of Modern Optics Special issue on 20 years of BEC

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Cited by in corpus (10)

• The Fulde-Ferrell-Larkin-Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review
• Exotic pairing state in quasicrystalline superconductors under magnetic field
• Fulde-Ferrell-Larkin-Ovchinnikov pairing as leading instability on the square lattice
• Spin-Imbalanced Pairing and Fermi Surface Deformation in Flat Bands
• Larkin-Ovchinnikov superfluidity in a two-dimensional imbalanced atomic Fermi gas
• Spin-Imbalanced Fermi Superfluidity in a Lieb Lattice Hubbard Model
• Superfluid weight and Berezinskii-Kosterlitz-Thouless temperature of spin-imbalanced and spin-orbit-coupled Fulde-Ferrell phases in lattice systems
• Momentum space imaging of the FFLO state
• Stabilising Fulde-Ferrel-Larkin-Ovchinnikov Superfluidity with long-range Interactions in a mixed dimensional Bose-Fermi System
• Finite momentum condensate brought on by Zeeman field