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The effect of ion bombardment with Ar+ and Kr+ on Co(1120) has been studied by means of low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS). At 300 K, the ion bombardment leads to the formation of a regularly stepped surface, as determined by the diffraction pattern. A geometrical evaluation of this pattern allowed development of a model of the stepped surface. The step width is found to vary between 1.4 ± 0.5 nm and 2.8 ± 0.5 nm corresponding to 3–5 or 6–8 unit cells, respectively. The step depth of 0.12 ± 0.02 nm is identical to the atomic distance between two consecutive layers of the Co(1120) surface. The orientation of the edges is preferentially parallel to the [1100] direction. As formation of these steps due to stabilisation by implanted noble gas atoms can be excluded, an alternative explanation is discussed, which combines anisotropic properties of the surface and kinetic effects, similar to the layer restricted diffusion (LRD) model. |
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