Diffusion of adatoms and small clusters on magnesium oxide surfaces

Abstract

The diffusion of isolated adatoms and small clusters is reviewed for transition and noblemetals adsorbed on the (001) surface of magnesium oxide. While isolated adatomsdiffuse by hopping among adsorption sites, small clusters such as dimers, trimersand tetramers already display a variety of diffusion mechanisms, from clusterhopping to rotation, sliding, leapfrog, walking, concertina, flipping, twisting, rollingand rocking. Since most of the available results are computational, the review ismostly related to theoretical work. Connection to experiments is discussed wherepossible, mostly by dealing with the consequences that adatom and small clustermobility may have on the growth of larger aggregates on the MgO(001) surface.