NONLOCAL CONDUCTIVITY IN THE VORTEX-LIQUID REGIME OF A 2-DIMENSIONAL SUPERCONDUCTOR

We have simulated the time-dependent Ginzburg-Landau equation with the rmal fluctuations, to study the nonlocal de conductivity of a supercon ducting film. Having examined points in the phase diagram at a wide ra nge of temperatures and fields below the mean field upper critical fie ld, we find a portion of the vortex-liquid regime in which the nonloca l Ohmic conductivity in real space is negative over a distance several times the spacing between vortices. The effect is suppressed when dri ven beyond linear response. Earlier work had predicted the existence o f such a regime, due to the high viscosity of a strongly correlated vo rtex liquid: This behavior is clearly distinguishable from the monoton ic spatial falloff of the conductivity in the higher temperature or fi eld regimes approaching the normal state. The possibilities for experi mental study of the nonlocal transport properties are discussed.