Surface composition and ordering of Cu₃Pt(111)

The surface composition and ordering of a Cu₃Pt(111) single crystal have been investigated by low energy alkali ion scattering and low energy electron diffraction. No surface chemical ordering and reconstruction have been evidenced. Using 1 keV Li⁺ ion scattering with calibration measurements on pure Cu(111) and Pt(111), the Pt composition (under thermal equilibrium conditions) in the first and second layers has been determined to be 0.20±0.02 and 0.31±0.06 respectively. A combination of a shadowing analysis with computer simulations reveals that the Pt atoms are coplanar with the Cu atoms in the first layer. The results also indicate that the Pt atoms in the first layer are not clustered in domains. This evidence has been confirmed by lack of the PtPt pair double scattering peak along the two long azimuthal directions using K⁺ ion scattering. © 1995.