Eur. Phys. J. B (2013) 86: 24
https://doi.org/10.1140/epjb/e2012-30216-x

Regular Article

Superconducting-insulator transition in disordered Josephson junctions networks

¹ Physics Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
² Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy
³ Istituto dei Sistemi Complessi, ISC-CNR Roma, Italy
⁴ ETH Swiss Federal Institute of Technology, 8006 Zurich, Switzerland

^a e-mail: anna.carbone@polito.it

Received: 11 March 2012
Received in final form: 19 June 2012
Published online: 28 January 2013

Abstract

The superconducting-insulator transition is simulated in disordered networks of Josephson junctions with thermally activated Arrhenius-like resistive shunt. By solving the conductance matrix of the network, the transition is reproduced in different experimental conditions by tuning thickness, charge density and disorder degree. In particular, on increasing fluctuations of the parameters entering the Josephson coupling and the Coulomb energy of the junctions, the transition occurs for decreasing values of the critical temperature T_c and increasing values of the activation temperature T_o. The results of the simulation compare well with recent experiments where the mesoscopic fluctuations of the phase have been suggested as the mechanism underlying the phenomenon of emergent granularity in otherwise homogeneous films. The proposed approach is compared with the results obtained on TiN films and nanopatterned arrays of weak-links, where the superconductor-insulator transition is directly stimulated.