Numerical study of conductance distribution in granular metal films

We study the shape of distribution F(G) for the conductance G between a poi nt on the surface of a metal-insulator nanocomposite film and the conductin g substrate. Random resistor networks with both metallic and tunneling bond s included are used to model nanocomposite films. Our simulation results sh ow explicitly that the shape of F(G) is determined mainly by the connectivi ty of metal particles and the maximum tunneling distance in the composite. By applying our results to the available experimental data on granular NiFe -SiO2, we find important implications for the understanding of microscopic conduction mechanisms near the metal-insulator transition. (C) 2000 America n Institute of Physics. [S0021-8979(00)02903-0].