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 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 For finite systems, however, we find both in simulations and experiments that the change in the current-voltage characteristics caused by the finite size shows a scaling property with an exponent seemingly suggesting a vanishing resistance at a temperature for which It is pointed out that the dynamic critical exponent found in Pierson et al. corresponds to the exponent 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 appears to be a common and intriguing feature for the finite size caused change in the characteristics around the KT transition.
- Received 2 March 2000
DOI:https://doi.org/10.1103/PhysRevB.62.14531
©2000 American Physical Society