Population imbalanced lattice fermions near the BCS-BEC crossover: II. The FFLO regime and its thermal signatures

Abstract

We study the effect of high population imbalance in the two dimensional attractive Hubbard model, in the coupling regime corresponding to BCS-BEC crossover, and focus on thermal effects on the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. Using a method that retains all the classical thermal fluctuations on the FFLO state we estimate a very low $T_c$ and infer a strongly first order normal state to FFLO transition. The $T_c$ is an order of magnitude below the mean field estimate. We track the fermionic momentum distribution, the density of states, and the pairing structure factor deep into the normal state. The pairing structure factor retains weak signature of finite momentum pairing to a high temperature despite the low $T_c$ itself, while the spin resolved density of states changes from the `pseudogapped' FFLO character to gapless and pseudogapped again with increasing temperature. These results map out the rather narrow temperature window, and diverse physical indicators, relevant to FFLO states on a cold atom optical lattice, and complements our work on the lower field `breached pair' state.

10 pages, 10 figures. This version and arXiv:1508.00393 are published as a combined text

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Cited by in corpus (14)

• The Fulde-Ferrell-Larkin-Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review
• Non Fermi liquid behavior and continuously tunable resistivity exponents in the Anderson-Hubbard model at finite temperature
• Doping-controlled transition from excitonic insulator to semimetal in Ta${}_2$NiSe${}_5$
• Strain induced superconductor-insulator transition on Lieb lattice
• Mutual information, quantum phase transition, and phase coherence in Kondo systems
• Development of long-range phase coherence on the Kondo lattice
• Thermal transitions, pseudogap behavior and BCS-BEC crossover in Fermi-Fermi mixtures
• Stability of the Fulde-Ferrell-Larkin-Ovchinnikov states in anisotropic systems and critical behavior at thermal $m$-axial Lifshitz points
• Non-collinear order and gapless superconductivity in s-wave magnetic superconductors
• Fulde-Ferrell-Larkin-Ovchinnikov state in strongly correlated d-wave superconductors
• Spin-orbital liquids and insulator-metal transitions on the pyrochlore lattice
• Anomalous pseudogap in population imbalanced Fermi superfluids
• Transport and spectroscopic signatures of a disorder-stabilized metal in two-dimensional frustrated Mott insulators
• Temperature tuned Fermi surface topology and segmentation in non-centrosymmetric superconductors