By using bond-counting arguments and embedded-atom calculations, the critical importance of dimer shearing in metal (100) sub-monolayer epitaxy was established. This process provided the easiest path for the diffusion of compact clusters of 4, 6 and 8 atoms, and introduced a wide variety of localized cluster dynamics. A combination of dimer shear motion, and sequential motion of individual atoms, provided a better interpretation to be made of the oscillatory behavior of cluster mobility as a function of cluster size. This also defined a new set of critical cluster sizes that were likely to be selected during epitaxial growth.

Z.P.Shi, Z.Zhang, A.K.Swan, J.F.Wendelken: Physical Review Letters, 1996, 76[26], 4927-30