Charging Effects and Quantum Crossover in Granular Superconductors
Abstract
The effects of the charging energy in the superconducting transition of granular materials or Josephson junction arrays is investigated using a pseudospin one model. Within a mean-field renormalization-group approach, we obtain the phase diagram as a function of temperature and charging energy. In contrast to early treatments, we find no sign of a reentrant transition in agreement with more recent studies. A crossover line is identified in the non-superconducting side of the phase diagram and along which we expect to observe anomalies in the transport and thermodynamic properties. We also study a charge ordering phase, which can appear for large nearest neighbor Coulomb interaction, and show that it leads to first-order transitions at low temperatures. We argue that, in the presence of charge ordering, a non monotonic behavior with decreasing temperature is possible with a maximum in the resistance just before entering the superconducting phase.
Cite
@article{arxiv.cond-mat/9309023,
title = {Charging Effects and Quantum Crossover in Granular Superconductors},
author = {E. Granato and M. A. Continentino},
journal= {arXiv preprint arXiv:cond-mat/9309023},
year = {2009}
}
Comments
15 pages plus 4 fig. appended, Revtex, INPE/LAS-003