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

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.