Strain-driven formation of two-dimensional holes on Cu(111) after the deposition of Fe

The formation and growth of one-monolayer-deep holes after the deposition of Fe on a Cu(111) vicinal surface at 300 K are studied by scanning tunneling microscopy (STM). At low Fe coverages, hole formation starts between separate Fe islands grown at step edges. As hole formation is accompanied by the creation of edge energy, it is assumed that the tensile stress field between the adjacent Fe islands provides the driving force for this process. At higher Fe coverages, another hole formation process is induced by the strain field at Fe wires, resulting in a step-up diffusion. Both hole-creating processes can be suppressed by depositing Fe at lower temperatures and subsequently sealing Cu steps and Fe wires by depositing Au. (C) 1997 Elsevier Science B.V.