A Cu(1 1 1)(√3×√3)R30°-Sb structure by impact collision ion-scattering spectroscopy

We have investigated the structures of Cu(1 1 1)(√3×√3)R30°-Sb using time of flight-impact collision ion-scattering spectroscopy. The experimental data and computer simulations support a structural model for the Cu(1 1 1)(√3×√3)R30°-Sb structure in which Sb atoms displace up to 1/3 of the first layer of Cu atoms and incorporate them into the first Cu layer with the Sb atoms displaced outward 0.40 Å with respect to the first-layer Cu atoms. The outermost first layer of Sb and Cu atoms shift from fcc- to hcp-hollow sites (only the top layer of Sb and Cu atoms occupies hcp hollow sites).