Complex impedance of a two-dimensional Josephson junction array

Simulations on the two-dimensional XY model are performed. The results are compared to experiments on a Josephson junction array for the case of a triangular lattice well below the Kosterlitz-Thouless temperature in a weak perpendicular magnetic field. Comparisons between experiments, existing theories and the simulations suggest that the characteristic features of the complex impedance seen in the experiments are due to vortex correlations induced by the presence of vortices with opposite vorticity. (C) 1997 Elsevier Science B.V.