Superfluid-ferromagnet-superfluid junction and the {pi} phase in a superfluid Fermi gas

Journal Article · Wed Sep 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.033617· OSTI ID:21456960

Kashimura, Takashi ^[1]; Tsuchiya, Shunji ^[2]; Ohashi, Yoji ^[1]

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1. Department of Physics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)
2. Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

We investigate the possibility of a superfluid-ferromagnet-superfluid (SFS) junction in a superfluid Fermi gas. To examine this possibility in a simple manner, we consider an attractive Hubbard model at T=0 within the mean-field theory. When a potential barrier is embedded in a superfluid Fermi gas with population imbalance (N{sub {up_arrow}}>N{sub {down_arrow}}, where N{sub {sigma}} is the number of atoms with pseudospin {sigma}= {up_arrow}, {down_arrow}), this barrier is shown to be magnetized in the sense that excess {up_arrow}-spin atoms are localized around it. The resulting superfluid Fermi gas is spatially divided into two by this ferromagnet, so that one obtains a junction similar to the superconductor-ferromagnet-superconductor junction discussed in superconductivity. Indeed, we show that the so-called {pi} phase, which is a typical phenomenon in the SFS junction, is realized, where the superfluid order parameter changes its sign across the junction. Our results would be useful for the study of magnetic effects on fermion superfluidity using an ultracold Fermi gas.

• OSTI ID: 21456960
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR MOMENTUM
ATOMS
CRYSTAL MODELS
DIMENSIONLESS NUMBERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FERMI GAS
FERMIONS
FERROMAGNETIC MATERIALS
FERROMAGNETISM
HUBBARD MODEL
MAGNETIC MATERIALS
MAGNETISM
MATERIALS
MATHEMATICAL MODELS
MEAN-FIELD THEORY
ORDER PARAMETERS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
POTENTIALS
SPIN
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SUPERFLUIDITY