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arXiv:cond-mat/0610610 · New Journal of Physics

Asymmetric fermion superfluid with inter- and intra-species pairings

Xu-Guang Huang, Xuewen Hao, Pengfei Zhuang

Published Oct 19, 2007• 7 citations
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Abstract

We investigate the phase structure of an asymmetric fermion superfluid with inter- and intra-species pairings. The introduction of the intra-species pairing mechanism in canonical ensemble changes significantly the phase diagram and brings in a new state with coexisting inter- and intra-species pairings. Different from the case with only inter-species pairing, all the fermion excitations are fully gapped in the region with intra-species pairing.

DOI
10.1088/1367-2630/9/10/375

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We explore ground states of asymmetrical Fermi systems where both inter- (go)({g}_{o})(go​) and intra- (g1)({g}_{1})(g1​) species pairing interactions are present. Using the equation of motion method, we obtain coupled mean-field equations for superfluid gap functions and population densities. We construct a phase diagram across BCS-BEC regimes. At low polarizations PPP, we find stable superfluid phases on BCS and BCS sides of unitarity for g1>g1c{g}_{1}>{g}_{1}^{c}g1​>g1c​, a critical value, for a given go{g}_{o}go​. For larger PPP, we find phase separations in both regimes. A superfluid phase exists for all polarizations deep in the BEC regime. Our results should apply to a broad range of Fermi systems.
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Abstract The ground state of spin-1/21/21/2 fermions with contact sss-wave inter- and ppp-wave intra-species interactions is discussed. Particularly, we formulate the mean field scheme for calculating thermodynamic properties of the system in arbitrary dimension D<2D<2D<2 and discuss in detail the phase diagram in the 1D case. Except for clean phases with either singlet or triplet Cooper pairings, we have identified two mixed phases (one stable and another metastable) of the one-dimensional two-component fermions where both pairing mechanisms coexist. PACS numbers: 67.85.-d