ENHANCEMENT IN NONLINEAR EFFECTS IN PERCOLATING NONLINEAR RESISTOR NETWORKS

The nonlinear response is studied in a percolating network of superconductor and normal conductor with nonlinear I-V characteristic below the percolation threshold of the superconductor. The crossover current density JL-NL, defined as the current density at which the linear and nonlinear responses of the network become comparable, is found to have a power-law dependence JL-NL (pc-p)H as the percolation threshold is approached from below. With use of a model of the percolating network below pc analogous to the nodes-links-blobs picture, H is found to be H=d(d-1)-1, where d is the correlation-length exponent and d is the dimensionality of the lattice. © 1990 The American Physical Society.