Mechanism of acoustically induced diffusional structuring of surface adatoms

Abstract

Physical mechanisms of time-averaged structuring of adatoms induced by a standing surface acoustic wave (SAW) on a solid substrate are studied. Despite some similarity with conventional mechanisms based on averaging of fast oscillation-type motion or radiation-pressure effects, we demonstrate that, for diffusional (i.e., strongly damped) adatom motion, the origin of time-averaged structuring is essentially different. The proposed analytical model and kinetic Monte–Carlo (kMC) simulations reveal several distinct structuring regimes and directly relate them to the transient modification of diffusion barriers and adiabatic temperature variations induced by SAW strains.