Stability conditions and Fermi surface topologies in a superconductor
arXiv:cond-mat/0603603 · doi:10.1103/PhysRevB.74.064505
Abstract
Candidate homogeneous, isotropic superfluid or superconducting states of paired fermion species with different chemical potentials, can lead to quasiparticle excitation energies that vanish at either zero, one, or two spheres in momentum space. With no zeroes, we have a conventional BCS superconductor. The other two cases, ``gapless'' superconductors, appear in mean field theory for sufficiently large mismatches and/or sufficiently large coupling strengths. Here we examine several stability criteria for those candidate phases. Positivity of number susceptibility appears to provide the most powerful constraint, and renders all the two-zero states that we have examined mechanically unstable. Our results should apply directly to ultracold fermionic atom systems.
18 pages, 7 figures; v2: some clarifications in Sec. IIC; references added; version accepted for publication in Phys. Rev. B
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- Two lectures on color superconductivity
- Phase diagram of a cold polarized Fermi gas
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Cited by in corpus (10)
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- Relativistic BCS-BEC crossover in a boson-fermion model
- Phase diagram of chiral quark matter: Fulde-Ferrell pairing from weak to strong coupling
- Anomalous specific heat jump in a two-component ultracold Fermi gas
- Gapless Surfaces in Anisotropic Superfluids
- Unconventional interaction between vortices in a polarized Fermi gas
- Magnetic Stability Analysis for Abelian and Non-Abelian Superconductors