Bombardment of (110) samples with Ar+ ions of normal incidence, at temperatures of 300 to 775K, created surface layer defects that generally spanned 1 or 2 unit cells (as revealed by scanning tunnelling microscopy). Vacancies which were produced in this way diffused via thermal activation to form single-layer vacancy islands. The diffusion of di-vacancies favored [1¯10], and accommodation at islands produced roughly isotropic islands. Modelling of this growth process revealed an overall Arrhenius behavior of the diffusion, with an activation energy of 1.3eV. Investigations of the surface morphology during multi-layer erosion revealed deviations from layer-by-layer removal, with scaling exponents of between 0.4 and 0.5 at temperatures of between 626 and 775K.

R.J.Pechman, X.S.Wang, J.H.Weaver: Physical Review B, 1995, 51[16], 10929-36