A SCANNING-TUNNELING-MICROSCOPY INVESTIGATION OF MBE-GROWN FE3O4(001)

We present STM images of Fe3O4 epitaxially grown on MgO(001) showing d etails of the surface structure including the surface reconstructions, the presence of monolayer steps on the surface, and the terrace width s. The p(1 x 1) surface is formed by a grouping of 2 to 4 atoms in the unit cell, to form a cluster that is elongated along a [110] directio n. Stacking fault defects are revealed by 90 degrees rotations of the surface reconstruction orientation observed on a single terrace, and b y the presence of bands devoid of the surface reconstruction separatin g the regions of different surface reconstruction orientation. Althoug h the oxygen atom positions in MgO and Fe3O4 are lattice matched to wi thin 0.3%, the difference in symmetry of the Fe and Mg atoms leads dir ectly to these faults.