Verification of a New Non-Linear IV-exponent: Simulation of the 2D Coulomb Gas with Langevin Dynamics.

Abstract

It has recently been suggested from scaling arguments that the non-linear IV-exponent a, for a two-dimensional superconductor is different from the exponent originally suggested by Ambegaokar et al. The relation between the new and the old exponent is a=a_AHNS-3. The new scaling behaviour is linked to the logarithmic vortex interaction and the long range time tail which this gives rise to. Consequently one may expect that the scaling behavior is generic for models which have these basic features. The simplest model of this type is the two-dimensional Coulomb gas model with Langevin dynamics. We here explicitly verify, through computer simulations, that the IV-characteristics of this model indeed scales according to the new scaling exponent a. Keywords: vortex, Coulomb gas, IV-exponent, Simulations, Langevin, 2D superconductor, thin films.

Submitted for publication in the proceedings of the Int. Workshop on Macroscopic Quantum Phenomena and Coherence in Supercond. Arrays, Villa Tuscolana, Frascati, Italy, March 2-5, 1995. Figures are included in the LaTeX document as PostScript specials. Related information as well as other formats (dvi, PS) is, or will be, made available at http://www.tp.umu.se/