Effective dimensionality crossover for superconducting surfaces in parallel magnetic fields

Journal Article · Sat Jan 01 04:00:00 EST 1977 · Phys. Rev., B; (United States)

DOI:https://doi.org/10.1103/PhysRevB.15.230· OSTI ID:7132649

Imry, Y

The superconducting fluctuations above T/sub c/ in the presence of a magnetic field parallel to the surface are known to be one dismensional (1D) in the bulk and 2D near the surface. The crossover between these two behaviors is studied as a function of the surface boundary condition on the parameter. Similar effects can be obtained due to the proximity of an additional surface, in the case of a film, as found by Thompson. The parameter governing the crossover is an effective mass related to the dependence of the eigenvalue of the Ginzburg-Landau equation on the distance from the surface. Predictions for the surface specific heat and static impedance and their crossovers from 1D to 2D behaviors are obtained. For a film with a ''critical'' thickness of approx. 1.8xi/sub T/, Gaussian exponents of 5/4 for the divergences of the above quantities are obtained. This corresponds to an effective dimensionality of 3/2, and is due to the fact that the dependence of the Ginzburg-Landau free energy on one of the momentum components becomes quartic. The same happens more generally in other k-space instabilities (Lifschitz multicritical points). The statement about the above effective change in dimensionality is also proved to order epsilon = 4 - d in a renormalization-group calculation. (AIP)

• Research Organization: Department of Physics, Brookhaven National Laboratory, Upton, New York 11973
• OSTI ID: 7132649
• Journal Information: Phys. Rev., B; (United States), Journal Name: Phys. Rev., B; (United States) Vol. 15:1; ISSN PLRBA
• Country of Publication: United States
• Language: English

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
FLUCTUATIONS
GINZBURG-LANDAU THEORY
MAGNETIC FIELDS
ONE-DIMENSIONAL CALCULATIONS
PHYSICAL PROPERTIES
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
SURFACES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VARIATIONS