Link between superstructures and kinetics in the CuSb(100) system

Abstract

We used dissolution and segregation kinetics to investigate the equilibrium superficial segregation of Sb on Cu(100). The kinetics are recorded by AES and the superficial superstructures determined from LEED patterns. Dissolution kinetics of one monolayer of Sb/Cu(100) stop for different superficial concentrations depending on the annealing temperature. Each superficial concentration corresponds to a particular superstructure which is indexed. A quasi-complete dissolution is obtained only for T = 770°C. The segregation kinetics of Sb recorded at different temperatures on the surface of a Cu(Sb)(100) solid solution (0.2 at%) reveal different slow downs which are related to the different superstructures. The set of results is interpreted in terms of local equilibrium between the surface and the selvedge. A schematic “2D” phase diagram is proposed. The isotherm obtained at 770°C is compared to those obtained for S/Cu(100) at the same temperature. The results are discussed in the frame of the classical segregation theory.