COMPARISON OF AN EXPERIMENTAL AND A THEORETICAL-STUDY OF THE SURFACE ALLOY PT CU(111)/

Electron spectroscopies have been used to characterise the surface all oy formed by annealing a nearly epitaxial thin film of Pt/Cu(111). The surface alloy extends over several monolayers and is the result of a non-classical dissolution of Pt into the Cu substrate. The surface lay er composition is Cu3Pt reminiscent of the L1(2) alloy phase. In the b ulk alloy this phase may be modelled using first neighbour effective p air interactions. This model is extended to the dissolution of a thin film of Pt into the Cu(111) substrate, by making use of the concept of local equilibrium. We show that at low temperature we can indeed stab ilise an L1(2) surface alloy phase