Analysis of current-voltage characteristics of two-dimensional superconductors: Finite-size scaling behavior in the vicinity of the Kosterlitz-Thouless transition

Kateryna Medvedyeva, Beom Jun Kim, and Petter Minnhagen
Phys. Rev. B 62, 14531 – Published 1 December 2000
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Abstract

It has been suggested [Pierson et al., Phys. Rev. B 60, 1309 (1999); Ammirata et al., Physica C 313, 225 (1999)] that for two-dimensional (2D) superconductors there exists a phase transition with the dynamic critical exponent z5.6. We perform simulations for the 2D resistively-shunted-junction model and compare the results with the experimental data in Repaci et al. obtained for an ultrathin YBCO sample [Phys. Rev. B 54, R9674 (1996)]. We then use a different method of analyzing dynamic scaling than in Pierson et al., and conclude that both the simulations and the experiments are consistent with a conventional Kosterlitz Thouless (KT) transition in the thermodynamic limit for which z=2. For finite systems, however, we find both in simulations and experiments that the change in the current-voltage (IV) characteristics caused by the finite size shows a scaling property with an exponent α1/6, seemingly suggesting a vanishing resistance at a temperature for which z=α1. It is pointed out that the dynamic critical exponent found in Pierson et al. corresponds to the exponent α1. It is emphasized that this scaling property does not represent any true phase transition since in reality the resistance vanishes only at zero temperature. Nevertheless, the observed scaling behavior associated with α1/6 appears to be a common and intriguing feature for the finite size caused change in the IV characteristics around the KT transition.

  • Received 2 March 2000

DOI:https://doi.org/10.1103/PhysRevB.62.14531

©2000 American Physical Society

Authors & Affiliations

Kateryna Medvedyeva, Beom Jun Kim, and Petter Minnhagen

  • Department of Theoretical Physics, Umeå University, 901 87 Umeå, Sweden

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Vol. 62, Iss. 21 — 1 December 2000

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