Competing pairing states for ultracold fermions in optical lattices with an artificial staggered magnetic field

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.013616· OSTI ID:21442965

Lim, Lih-King; Lazarides, Achilleas; Morais Smith, C ^[1]; Hemmerich, Andreas ^[2]

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1. Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, NL-3584 CE Utrecht (Netherlands)
2. Institut fuer Laser-Physik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany)

We study fermionic superfluidity in an ultracold Bose-Fermi mixture loaded into a square optical lattice subjected to a staggered flux. While the bosons form a Bose-Einstein condensate at very low temperature and weak interaction, the interacting fermions experience an additional long-ranged attractive interaction mediated by phonons in the bosonic condensate. This leads us to consider a generalized Hubbard model with on-site and nearest-neighbor attractive interactions, which give rise to two competing pairing channels. We use the Bardeen-Cooper-Schrieffer theory to determine the regimes where distinct fermionic superfluids are stabilized and find that the nonlocal pairing channel favors a superfluid state which breaks both the gauge and the lattice symmetries, similar to unconventional superconductivity occurring in some strongly correlated systems. Furthermore, the particular structure of the single-particle spectrum leads to unexpected consequences, for example, a dome-shaped superfluid region in the temperature versus filing fraction phase diagram, with a normal phase that contains much richer physics than a Fermi liquid. Notably, the relevant temperature regime and coupling strength are readily accessible in state of the art experiments with ultracold trapped atoms.

• OSTI ID: 21442965
• Journal Information: Physical Review. A, Vol. 82, Issue 1; Other Information: DOI: 10.1103/PhysRevA.82.013616; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
BCS THEORY
BOSE-EINSTEIN CONDENSATION
BOSONS
COUPLING
FERMI GAS
FERMIONS
HUBBARD MODEL
MAGNETIC FIELDS
PAIRING INTERACTIONS
PHASE DIAGRAMS
PHONONS
SUPERCONDUCTIVITY
SUPERFLUIDITY
TRAPPING
CRYSTAL MODELS
DIAGRAMS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INFORMATION
INTERACTIONS
MATHEMATICAL MODELS
PHYSICAL PROPERTIES
QUASI PARTICLES