Quantum Percolation in Granular Metals
Abstract
Theory of quantum corrections to conductivity of granular metal films is developed for the realistic case of large randomly distributed tunnel conductances. Quantum fluctuations of intergrain voltages (at energies E much below the bare charging energy scale E_{C}) suppress the mean conductance g¯(E) much more strongly than its standard deviation σ(E). At sufficiently low energies E_{*} any distribution becomes broad, with σ(E_{*})∼g¯(E_{*}), leading to strong local fluctuations of the tunneling density of states. The percolative nature of the metalinsulator transition is established by a combination of analytic and numerical analysis of the matrix renormalization group equations.
 Publication:

Physical Review Letters
 Pub Date:
 September 2004
 DOI:
 10.1103/PhysRevLett.93.136403
 arXiv:
 arXiv:condmat/0404350
 Bibcode:
 2004PhRvL..93m6403F
 Keywords:

 71.30.+h;
 64.60.Ak;
 73.23.Hk;
 Metalinsulator transitions and other electronic transitions;
 Renormalizationgroup fractal and percolation studies of phase transitions;
 Coulomb blockade;
 singleelectron tunneling;
 Condensed Matter  Mesoscopic Systems and Quantum Hall Effect;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 6 pages, 5 figures, REVTeX 4