Oxidation of the Cu(100)c(2x2)-Mn surface: epitaxial manganese oxide

Using a combination of scanning tunnelling microscopy (STM), low energy ele ctron diffraction and X-ray photoelectron spectroscopy the oxidation of the Cu(100)c(2 x 2)-Mn surface alloy phase has been studied. A commensurate (r oot 5 x root 5)R27 degrees phase is formed, the periodicity and stoichiomet ry of which are consistent with an epitaxial manganese oxide overlayer havi ng a structure very similar to that of bulk Mn3O4 ("hausmannite"). Possible detailed structural models for the oxide registry are discussed, especiall y in the light of the observed STM images. (C) 1998 Elsevier Science B.V. A ll rights reserved.