IONIC-DIFFUSION ON A LATTICE - EFFECTS OF THE ORDER-DISORDER TRANSITION ON THE DYNAMICS OF NONEQUILIBRIUM SYSTEMS

We examine the behaviour of the concentration profiles of particles wi th repulsive interactions diffusing on a host lattice. At low temperat ure, the diffusion process is strongly influenced by the presence of o rdered domains. We use mean field equations and Monte-Carlo simulation s to describe the various effects which influence the kinetic behaviou r. An effective diffusion coefficient is determined analytically and i s compared with the simulations. Finite gradient effects on the ordere d domains and on the diffusion are discussed. The kinetics studied is relevant for superionic conductors, for intercalation and also for the diffusion of particles adsorbed on a substrate.