Superconductor-insulator transition in a network of 2d percolation clusters
School of Mathematical Sciences, Queen Mary University of London - London E1 4NS, UK, EU
Received: 27 October 2012
Accepted: 11 January 2013
In this paper we characterize the superconductor-insulator phase transition on a network of 2d percolation clusters. Sufficiently close to the percolation threshold, for p ≃ pc, this network has a broad degree distribution, and at p = pc the degree distribution becomes scale free. We study the transverse Ising model on this complex topology in order to characterize the superconductor-insulator transition in a network formed by 2d percolation clusters of a superconductor material. We show, by a mean-field treatment, that the critical temperature of superconductivity depends on the maximal eigenvalue Λ of the adjacency matrix of the network. At the percolation threshold, p = pc, we find that the maximal eigenvalue Λ of the adjacency matrix of the network of 2d percolation clusters has a maximum. In correspondence of this maximum the superconducting critical temperature Tc is enhanced. These results suggest the design of new superconducting granular materials with enhanced critical temperature.
PACS: 64.60.aq – Networks / 64.60.ah – Percolation / 05.30.Rt – Quantum phase transitions
© EPLA, 2013