Surface structure determination of an oxide film grown on a foreign substrate:Fe3O4multilayer on Pt(111) identified by low energy electron diffraction

For the first time a detailed surface structure determination is reported for an oxide film grown on a foreign metal substrate. Well-ordered iron oxide films were grown onto Pt(111) substrates and were identified by a dynamical low energy electron diffraction analysis to be magnetite, ${\mathrm{Fe}}_3$ ${\mathrm{O}}_4$. They form an unreconstructed polar (111) surface termination that exposes 1/4 monolayer of Fe ions over a distorted hexagonal close-packed oxygen layer and minimizes the number of dangling bonds. The surface also exhibits large relaxations that may be driven by electrostatic forces.