Mechanisms for annealing of ion-bombardment-induced defects on Pt(111)

Abstract

The morphology of a Pt(111) crystal during bombardment with 600-eV ${\mathrm{Ar}}^{+}$ ions has been investigated at constant temperatures ${\mathit{T}}_{\mathit{s}}$ with thermal-energy atom scattering. Below ${\mathit{T}}_{\mathit{s}}$≲600 K the formation of three-dimensional (3D) structures is observed, while above ${\mathit{T}}_{\mathit{s}}$≳700 K the removal proceeds layer by layer. From the quantitative modeling of the data we infer that 3D structures develop when annealing proceeds only by intralayer diffusion of vacancies, while layer-by-layer removal is observed when interlayer mass transport also becomes effective. The latter process is believed to be related to the onset of meandering (roughening) of atomic steps.