The concept of acoustic activation of surface diffusion was explored theoretically and by atomistic simulation. It was found that a substantial diffusion enhancement by surface acoustic waves was possible via transient surface strain-induced modification of the diffusion barriers, by adiabatic variation in the surface temperature and by dynamic coupling of the acoustic waves with vibrational states of adsorbed species. The approximate scaling laws which described the first two effects were established and verified by kinetic Monte Carlo simulation. The combined contribution of all three effects was studied by molecular dynamics simulation, and the conditions for diffusion activation through the dynamic coupling were elucidated. The acoustic enhancement of surface diffusion provided an attractive alternative to thermal activation for thin-film growth on heat-sensitive substrates.

Acoustic Enhancement of Surface Diffusion. C.Wu, V.Y.Zaitsev, L.V.Zhigilei: Journal of Physical Chemistry C, 2013, 117[18], 9252-8