Potential-induced strain relaxation in Au mono- and bilayer films on Pt(111) electrode surfaces

A novel potential-iinduced restructuring of a heteroepitaxial metal film, resulting in a sequence of potential stabilized phases and potential-induced phase transitions in mono- and bilayer Au films on Pt(111) is reported. It is shown that the structures follow the same general principles of strain relaxation as they are derived for epitaxial metal-on-metal systems on hexagonal metal surfaces and described theoretically within the framework of the Frenkel-Kontorova model. Analogous to the potential-induced removal of the reconstruction of Au(111) a reduction in in-plane stress due to adsorption of anions is proposed as the driving force for these stuctural transitions.