Surface self-diffusion on Pt(110): Directional dependence and influence of surface-energy anisotropy

The decay of periodic surface profiles by surface self-diffusion is simulated by numerically solving the phenomenological equations for this process. The crystalline nature of the surface is taken into account by introducing an anisotropic surface free energy,(). Depending on the degree of anisotropy of(), the decay kinetics and the shapes of the profiles are largely different. A comparison with measurements of profile decay on Pt(l10) single crystal surfaces shows that the anisotropy in() along the [1¯10] azimuth should be about 2–3%, while that along the [001] azimuth is expected near 8%. In the latter case large amplitude profiles exhibit (111) faceting and slow decay kinetics which are non-exponential. The rate of surface self-diffusion on Pt(110) is anisotropic with the [1¯10] direction being faster than the [001] direction.