Method of creating a Pd-covered single-atom sharp W pyramidal tip: Mechanism and energetics of its formation

Single-atom sharp pyramidal W tips, wrapped in a Pd overlayer, having atom-perfect wedges can be routinely and repeatedly created using a surface-science technique. This single-atom tip is thermally stable up to 1000 K because of the exceptionally large surface-energy anisotropy of the Pd covered W(111) surface. We conclude from atom-by-atom analysis that the W tip is covered with only one physical monolayer of Pd. We also investigate the mechanism and energetics of the atomic processes involved in its formation.