Renormalization and the Kosterlitz-Thouless transition in a two-dimensional superconductor
The nonlinear I-V characteristics of thin high-sheet-resistance Hg-Xe alloy films are examined within the context of the Kosterlitz-Thouless theory of the superconducting transition. In the regime below the vortex-unbinding temperature T/sub c/, where logarithmically bound vortices can be broken apart by a transport current, we find that Vapprox.I/sup a/(T). Comparison with theory allows us to infer the value of T/sub c/ and the mean-field temperature T/sub c/0 from a(T), and the dependence of these temperatures on R/sub N//sup D'Alembertian/ appears in approximate agreement with the microscopic theory of dirty superconductors. A systematic deviation appears to be consistent with renormalization of the vortex interaction close to T/sub c/ due to the presence of small polarizable vortex pairs, and can be described by an effective vortex dielectric constant epsilon/sub c/ = 1.2. Further evidence for this renormalization, which is a key feature of the Kosterlitz-Thouless transition, is obtained by examining the curvature of the logV vs logI plot very close to T/sub c/. The current dependence of a(I,T) = d(logV)/d(logI) is a direct measure of the spatial dependence of the vortex interaction, allowing a direct comparison with the analytic predictions of the renormalization equations. Satisfactory agreement is obtained using physically reasonable parameters.
- Research Organization:
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455
- OSTI ID:
- 5994564
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 27:11; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
MERCURY ALLOYS
NONLINEAR PROBLEMS
PHYSICAL PROPERTIES
RARE GAS COMPOUNDS
RENORMALIZATION
SUPERCONDUCTIVITY
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
VORTICES
XENON COMPOUNDS