Interfacial strain-enhanced reconstruction of Au multilayer films on Rh(100)

The Au(100) surface reconstructs to a contracted, hexagonal-close-packed (hcp) surface layer at or below 373 K. This study investigates the consequence of film-substrate interactions, in particular lattice mismatch, on Au(100) reconstruction by looking at the Au/Rh(100) interface which has a 7% mismatch strain. Monte Carlo simulations using the Rafii-Tabar-Sutton-Chen parametrization of the Finnis-Sinclair pseudo-many-body potential find that Au films on Rh(100) exhibit a structural transition to a hcp-type adlayer at significantly lower temperatures than pure Au(100). Furthermore, the extent of the hcp regions (observed as striped domains) is temperature and coverage dependent. For instance, for coverages up to 1.0 ML of Au, the structure of the adlayer is pseudomorphic, while multilayer Au films exhibit this reconstruction. These results lead to the conclusion that lattice mismatch provides an additional driving force for Au(100) reconstruction in multilayer Au films.