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Quantum percolation in granular metals

M. V. Feigel'man·A. S. Ioselevich·M. A. Skvortsov
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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 bare charging energy scale E_C) suppress the mean conductance \bar{g}(E) much stronger than its standard deviation σ(E). At sufficiently low energies E_* any distribution becomes broad, with σ(E_*) ~ \bar{g}(E_*), leading to strong local fluctuations of the tunneling density of states. Percolative nature of metal-insulator transition is established by combination of analytic and numerical analysis of the matrix renormalization group equations.

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M. V. Feigel'man, A. S. Ioselevich, M. A. Skvortsov. 2004-04-15. Quantum percolation in granular metals. https://doi.org/10.1103/physrevlett.93.136403

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