LINK BETWEEN SUPERSTRUCTURES AND KINETICS IN THE CU-SB(100) SYSTEM

We used dissolution and segregation kinetics to investigate the equili brium superficial segregation of Sb on Cu(100). The kinetics are recor ded by AES and the superficial superstructures determined from LEED pa tterns. Dissolution kinetics of one monolayer of Sb/Cu(100) stop for d ifferent superficial concentrations depending on the annealing tempera ture. Each superficial concentration corresponds to a particular super structure which is indexed. A quasi-complete dissolution is obtained o nly for T = 770-degrees-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 differe nt superstructures. The set of results is interpreted in terms of loca l equilibrium between the surface and the selvedge. A schematic ''2D'' phase diagram is proposed. The isotherm obtained at 770-degrees-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 .