Nanopattern-stimulated superconductor-insulator transition in thin TiN films

We present the results of the comparative study of transport properties of continuous and nanoperforated TiN films, enabling us to separate the disorder and the geometry effects. Nanopatterning transforms a thin TiN film into an array of superconducting weak links and eo ipso stimulates the disorder and magnetic-field driven superconductor-to-insulator transitions, shifting both transitions to a lower degree of microscopic disorder. We observe magnetoresistance oscillations reflecting collective phase-frustration behaviour of the multiconnected superconducting weak link network in a wide range of temperatures. We find that nanopatterning enhances the role of the two-dimensional Coulomb interaction and changes the characteristic energies of the film on length scales significantly larger than the mean free path or the superconducting coherence length. Copyright (C) EPLA, 2011