Time evolution of the local slope during Cu(110) ion sputtering

The time evolution of the morphology of the Cu(110) surface during ion sputtering has been studied in situ and in real time by x-ray-based techniques. The surface was bombarded with Ar+ ions at an energy of 1 keV in the temperature range 100-320 K; the ion incidence angle was set out of the x-ray scattering plane in order to induce asymmetric nanostructures. The results show that the ripples or mounds formed by the ion sputtering evolve in time, changing the spatial periodicity and the local slope of the facets. The latter is strongly dependent on temperature; moreover the facets along the <1-10> direction evolve in a different way from those along <001>.