Diffusion and conduction in percolation systems

Abstract

Percolation is a standard model for disordered systems. Its applications range from transport in amorphous and porous media and composites to the properties of branched polymers, gels and complex ionic conductors. Because of universality the results do not depend on the specific model, and general scaling laws can be deduced. In this chapter we give a short introduction to percolation theory and describe one application to composites. We start with the structural properties of site percolation clusters and their substructures and report on other percolation systems after that. Then we turn to the dynamical properties of percolation clusters and discuss the way the laws of diffusion and conduction are modified on random fractal structures. Finally, we review a particular application of the percolation concept, transport in heterogeneous ionic conductors.