A detailed view of the diffusion of Si dimers on the (001) surface was presented. By using a combination of atom tracking and ab initio modelling, the dimer was shown to move one atom at a time rather than as a 2-atom unit. The details of the pathway depended on the diffusion channel. On top of dimer rows, the 2 atoms of a dimer separated but remained bound during diffusion. In the troughs between dimer rows, the 2 atoms separated completely and moved independently before re-joining at a new location.

Piecewise Diffusion of the Silicon Dimer B.Borovsky, M.Krueger, E.Ganz: Physical Review B, 1999, 59[3], 1598-601