CoO(111) surface study by surface X-ray diffraction

Abstract

We present a structural investigation of the polar (111) surface of CoO single crystals by grazing incidence X-ray diffraction. The surface is found to be always covered by a ∼50 Å-thick spinel Co 3O 4 layer that was quantitatively characterized. Attempts to remove this layer by UHV annealings or Ar + bombardments lead to the formation of metallic Co clusters on the surface that transform again in Co 3O 4 by annealing under oxygen.