title: Initial stages of Cu3Au(111) oxidation: oxygen induced Cu segregation and the protective Au layer profile.
abstract: We report results of our experimental and theoretical studies on the Au concentration profile of Cu3Au(111) during oxidation by a hyperthermal O2 molecular beam at room temperature, using X-ray photoemission spectroscopy (XPS), in conjunction with synchrotron radiation (SR), and density functional theory (DFT). Before O2 exposure, we observe strong Au segregation to the top layer, i.e., Au surface enrichment of the clean surface. We also observe a gradual Cu surface enrichment, and Au enrichment of the second and third (subsurface) layers, with increasing O coverage. Complete Cu segregation to the surface occurs at 0.5 ML O surface coverage. The Au-rich second and third layers of the oxidized surface demonstrate the protective layer formation against oxidation deeper into the bulk.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan. okada@chem.sci.osaka-u.ac.jp.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Tsuda
authors.forename: Kohei
authors.initials: K
authors.lastname: Oka
authors.forename: Takamasa
authors.initials: T
authors.lastname: Makino
authors.forename: Michio
authors.initials: M
authors.lastname: Okada
authors.forename: Wilson Agerico
authors.initials: WA
authors.lastname: Diño
authors.forename: M
authors.initials: M
authors.lastname: Hashinokuchi
authors.forename: Akitaka
authors.initials: A
authors.lastname: Yoshigoe
authors.forename: Yuden
authors.initials: Y
authors.lastname: Teraoka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kasai