Possibility of a metallic phase in granular superconducting films - art. no. 144509

We investigate the possibility of finding a zero-temperature metallic phase in granular superconducting films, modeled as a dissipative Bose system. W e extend the conventional treatment of these systems to a formalism that ca n distinguish between insulator, metal, and superfluid phases. We do not fi nd a metallic state at zero temperature. At finite temperatures, we find th at the system exhibits a crossover between superfluid and metallic behavior . This has implications for the analysis of experimental results that makes use of a scaling hypothesis involving only a single parameter. We also inv estigate the effect of vortex dissipation in these systems.