Ginzburg-Landau theory of superconductors with short coherence length
- Sektion Physik, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, D-80333 Muenchen (Germany)
We consider fermions in two dimensions with an attractive interaction in the singlet d-wave channel of arbitrary strength. By means of a Hubbard-Stratonovich transformation a statistical Ginzburg-Landau theory is derived, which describes the smooth crossover from a weak-coupling BCS superconductor to a condensate of composite bosons. We show that the Nelson-Kosterlitz jump in the superfluid density vanishes in the BCS limit, where mean-field theory becomes exact. Adjusting the interaction strength to the observed slope of H{sub c{sub 2}} at T{sub c} in the optimally doped high-T{sub c} compounds Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O, we determine the associated values of the Ginzburg-Landau correlation length {xi} and the London penetration depth {lambda}. The resulting dimensionless ratio k{sub F}{xi}(0){approx}5{minus}8 and the Ginzburg-Landau parameter {kappa}={lambda}/{xi}{approx}90{minus}100 agree well with the experimentally observed values. These parameters indicate that the optimally doped materials are still on the weak-coupling side of the crossover to a Bose regime. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 633986
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 14; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
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