General analytical expressions for the chemical and jump diffusion coefficients were derived in the case of strong inhomogeneity for lattices of various symmetries. It was shown that the character of the particle migration depended crucially on the relative jump frequencies of particles located in deep and shallow sites. If these frequencies differ insignificantly, particle diffusion proceeds by single uncorrelated jumps, while widely differing jump frequencies result in pairs of strongly correlated jumps. The expressions were checked for the case of square inhomogeneous lattice using kinetic Monte Carlo simulations. Here, the results of particle migration over three-dimensional inhomogeneous simple cubic lattice were presented. The density dependences obtained by the analytical expressions for different temperatures and signs of the lateral pair-wise interaction were compared with the results of the direct kinetic Monte Carlo simulations of the particle diffusion. Almost perfect agreement between the respective results was found.

Modeling Diffusion on Heterogeneous Lattices: Simple Cubic Lattice. A.Tarasenko, L.Jastrabik, T.Müller: Physical Review B, 2007, 76[13], 134201