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The process of electronic conduction in granular metals in the dielectric regime is being considered. The charging energy model of conduction in granular metals recently proposed in the literature, is extended to include the effect of the clustering of metallic component which takes place when metal-insulator transition is approached. The electrical conduction is modeled by a resistor lattice built from conductances, Gij equals G0exp(-2chisij-EijlkT), where (chi) is the decay rate of the electron wave function in the insulator, k is Boltzmann's constant and sij and Eij are intergrain separation and intergrain charging energy respectively. The process of clustering of metallic component is introduced as highly conductive bonds which appear in the lattice with average number of B bonds per lattice site. The critical path method is used to find the conductivity, (sigma) , of the model. Temperature dependence of, (sigma) approximately equals exp[-(T1/T)1/2] in agreement with widely observed experiments is found. The temperature, T1, is found to decrease with B increasing i.e. when metal-insulator transition is approached in agreement with experiments reported for real granular metals. Numerical simulations of the model are performed. Quite good agreement between the critical path analysis and numerical data is found.
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