Coherence lengths for three-dimensional superconductors in the BCS-Bose picture
- Department of Physics, University of Pretoria, 0002 Pretoria (South Africa)
- Departament de Fisica, Universitat de les Illes Balears, 07071 Palma de Mallorca (Spain)
- Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)
- Vista University, P/Bag X1311, 0127 Silverton (South Africa)
Following an approach similar to that of Miyake or Randeria, Duan, and Shieh in two dimensions, we study a three-dimensional many-fermion gas at zero temperature interacting via some short-ranged two-body potential. To accommodate a possible singularity (e.g., the Coulomb repulsion) in the interaction, the potential is eliminated in favor of the two-body scattering {ital t}-matrix, the low-energy form of which is expressible in terms of the {ital s}-wave scattering length {ital a}{sub {ital s}}. The BCS gap equation for {ital s}-wave pairing is then solved simultaneously with the number equation in order to self-consistently obtain the zero-temperature BCS gap {Delta} as well as the chemical potential {mu} as functions of the dimensionless coupling variable {lambda}{equivalent_to}{ital k}{sub {ital F}}{ital a}{sub {ital s}}, where {ital k}{sub {ital F}} is the Fermi momentum. Results are valid for arbitrary coupling strength, and in the weak coupling limit reproduce the standard BCS results. Finally, root-mean-square pair sizes are obtained as a function of {lambda} and compared with experimental values.
- OSTI ID:
- 147774
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 52, Issue 22; Other Information: PBD: 1 Dec 1995
- Country of Publication:
- United States
- Language:
- English
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