Interlayer interactions in epitaxial oxide growth: FeO on Pt(111)

We have studied the first monolayer of epitaxial iron oxide on Pt(111) with x-ray photoelectron diffraction and other methods. We confirm a previously proposed superlattice model for this monolayer, but also conclude that the oxide grows as a bilayer of FeO(111) with the oxygen layer outermost, the Fe-O interlayer distance is highly compressed relative to bulk FeO by about 50%, and only one of two possible domains forms due to interlayer interactions between oxygen and platinum.