Current-voltage characteristics and vortex-glass phase of diluted Josephson-junction arrays in a magnetic field

Dynamical simulations are used to study the current-voltage characteristics of two-dimensional Josephson-junction arrays with an average flux quantum per plaquette f and random dilution of junctions. For f = 1/2, we find evid ence of a phase coherence threshold value x(s), below the percolation conce ntration x(p), where the superconducting transition vanishes. For x(s) < x < x(p) the array behaves as a zero-temperature vortex glass with nonzero li near resistance at finite temperatures. We also find that the critical curr ents at zero temperature are less sensitive to variations in f in this rang e of dilutions. (C) 2000 Elsevier Science B.V. All rights reserved.