DYNAMICAL UNIVERSALITY CLASSES OF THE SUPERCONDUCTING PHASE-TRANSITION

We present a finite temperature Monte Carlo study of the XY model in t he vortex representation and study its dynamical critical behavior in two limits. The first neglects magnetic-field fluctuations, correspond ing to the absence of screening, which should be a good approximation in high-T-c superconductors (kappa-->infinity) except extremely close to the critical point. Here, from finite-size scaling of the linear re sistivity we find the dynamical critical exponent of the vortex motion to be z approximate to 1.5. The second limit includes magnetic-field fluctuations in the strong screening limit (kappa-->0) corresponding t o the true asymptotic inverted XY critical regime, when we find the un expectedly large value z approximate to 2.7. We compare these results, obtained from dissipative dynamics in the vortex representation, with the universality class of the corresponding model in the phase repres entation with propagating (spin-wave) modes. We also discuss the effec t of disorder and the relevance of our results for experiments.