STRUCTURES OF A AG MONOLAYER DEPOSITED ON CU(111), CU(100), AND CU(110) SUBSTRATES - AN EXTENDED TIGHT-BINDING QUENCHED-MOLECULAR-DYNAMICS STUDY

We determine the atomic structure of a Ag monolayer deposited on the three low-index faces of a Cu substrate by means of an extended tight-binding quenched-molecular-dynamics simulation. For the (111) face, the most stable structure is a p(10 X 10) one. The surface plane is strongly waving, the perturbation extending up to the first ten surface layers. For the (100) face, the pseudohexagonal reconstruction c(10 X 2) is stablized with respect to pseudomorphy and pseudoepitaxy. The case of the (110) face is more intricate. As a function of the Ag coverage, we predict a sequence of superstructures going from the p(2 X 7) missing-row reconstruction at low coverage up to the pseudohexagonal p(7 X 2) reconstruction at the monolayer completion.