The growth and atomic structures of epitaxial iron-oxide films on Pt(111) were studied with scanning tunneling microscopy and high-resolution low-energy electron diffraction. During the initial layer-by-layer growth of FeO(111) four different structures are formed as the coverage increases to 2.5 monolayers, then a three-dimensional growth of ${\mathrm{Fe}}_3{\mathrm{O}}_4\mathrm{}\left(111\right)\mathrm{}$ islands begins. The structural transformations demonstrate that the relaxations within the FeO(111) films and the Stranski-Krastanov growth mode are induced by electrostatic surface energies, which dominate the energetics of thin film systems made up of ionic compound materials.

• Received 28 December 1998

DOI:https://doi.org/10.1103/PhysRevB.60.1527