Two approaches to studying diffusion and segregation on the surfaces 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 prohibitive. It was shown that a combination of temperature accelerated dynamics together with kinetic Monte Carlo methods could reach the times-scales required without the necessity of (often incorrectly) guessing which were the dominant processes. The power of the methods for surface diffusion and the growth of rock-salt oxides was illustrated. It was shown that exchange mechanisms and correlated ion motions were surprisingly important in surface and near-surface diffusion of those ionic systems. Another approach, exchange Monte Carlo, was used to study equilibrium segregation in thin ceramic films with application to MgO/MnO. Surface concentrations as a function of temperature and film composition were determined directly from the simulations. For all compositions studied the {001} surface was Mn2+-rich; the occupancy of sites by Mn2+ decreased rapidly with depth.

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