Two approaches to studying diffusion and segregation at the surface of oxides and ceramics were demonstrated. When simulating surface diffusion, the activation barriers were often so high that the time-scales required for direct simulation by molecular dynamics were too long. It was shown that a combination of temperature accelerated dynamics, together with kinetic Monte Carlo methods, could approach the timescales required, without the need to guess which were the predominant processes. It was shown that exchange mechanisms and correlated ion motions were important in surface and near-surface diffusion of ionic systems. Exchange Monte Carlo methods were used to study equilibrium segregation in thin ceramic films, and surface concentrations as a function of temperature and film composition were determined directly from the simulations.

Atomistic Simulations of Surface Diffusion and Segregation in Ceramics. M.Y.Lavrentiev, N.L.Allan, J.H.Harding, D.J.Harris, J.A.Purton: Computational Materials Science, 2006, 36[1-2], 54-9