Molecular dynamics calculations using analytical potential functions with polarizable oxygen ions were used to identify a novel mode of reconstruction on the half-occupied tetrahedral layer termination of the magnetite (Fe3O4) (001) surface. In the proposed reconstruction, the twofold coordinated iron ion in the top monolayer rotated downward to occupy a vacant half-octahedral site in the plane of the second-layer iron ions. At the same time, half of the tetrahedral iron ions in the third iron layer were pushed upward to occupy an adjacent octahedral vacancy at the level of the second-layer iron ions. The other half of the third-layer iron ions remain roughly in their original positions. The proposed reconstruction was consistent with low-energy electron diffraction and X-ray photo-electron spectroscopy results. It also provides a compelling interpretation for the arrangement of atoms suggested by high-resolution scanning-tunnelling microscopy studies.

A Molecular Dynamics Investigation of Surface Reconstruction on Magnetite (001). J.R.Rustad, E.Wasserman, A.R.Felmy: Surface Science, 1999, 432[1-2], L583-8