Structure, translational state and morphology of the Ag/MgO(001) interface during its formation

The structure and morphology of the Ag/MgO(0 0 1) interface have been investigated in situ by grazing incidence X-ray diffraction during the first stages of Ag deposition by molecular beam epitaxy. At the very beginning, Ag is perfectly registered, consisting of wide, one monolayer high platelets that cover half of the surface. The growth then proceeds in the form of islands, with Ag relaxation on surfaces. Finally, plastic relaxation occurs through a misfit dislocation network. The epitaxial site (on top of oxygen atoms) and interfacial distance are experimentally determined for the first time. Comparison with previous theoretical results on this model metal/insulator interface shows that the most recent ab initio calculations predict the correct interfacial structure.