Exotic Superconducting Phases of Ultracold Atom Mixtures on Triangular Lattices

Abstract

We study the phase diagram of two-dimensional Bose-Fermi mixtures of ultracold atoms on a triangular optical lattice, in the limit when the velocity of bosonic condensate fluctuations is much larger than the Fermi velocity. We contrast this work with our previous results for a square lattice system in Phys. Rev. Lett. {\bf 97}, 030601 (2006). Using functional renormalization group techniques we show that the phase diagrams for a triangular lattice contain exotic superconducting phases. For spin-1/2 fermions on an isotropic lattice we find a competition of $s$-, $p$-, extended $d$-, and $f$-wave symmetry, as well as antiferromagnetic order. For an anisotropic lattice, we further find an extended p-wave phase. A Bose-Fermi mixture with spinless fermions on an isotropic lattice shows a competition between $p$- and $f$-wave symmetry. These phases can be traced back to the geometric shapes of the Fermi surfaces in various regimes, as well as the intrinsic frustration of a triangular lattice.

6 pages, 4 figures, extended version, slight modifications

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Cited by in corpus (9)

• Supersolidity of cold-atom Bose-Fermi mixtures in optical lattices
• Pairing and density-wave phases in Boson-Fermion mixtures at fixed filling
• Unconventional Spin Density Waves in Dipolar Fermi Gases
• Phases and collective modes of hardcore Bose-Fermi mixture in an optical lattice
• Effects of a dilute gas of fermions on the superfluid-insulator phase diagram of the Bose-Hubbard model
• Correlated Phases of Population Imbalanced Fermi-Fermi Mixtures on an Optical Lattice
• Multipolar Fermi-surface deformation in a Rydberg-dressed Fermi gas with long-range anisotropic interactions
• Particle-Hole Asymmetry and Pinball Liquid in a Triangular-Lattice Extended Hubbard Model within Mean-Field Approximation
• Weak three-dimensional mediators of two-dimensional triplet pairing