Surface structure of MBE-grown Fe3O4(001) by X-ray photoelectron diffraction and scanning tunneling microscopy

We have investigated the surface termination and interlayer relaxations of (root 2 x root 2)R45 degrees-Fe3O4(001) as grown on MgO(001) by oxygen-plasma-assisted molecular beam epitaxy. Despite the fact that autocompensated surfaces can be constructed in principle by terminating with either a half layer of tetrahedral Fe, or a modified layer of octahedral Fe plus tetrahedral O, the combination of photoelectron diffraction and scanning tunneling microscopy suggests the former. The first four interlayer spacings are relaxed by -14, -57, -19, and +29% of the respective bulk value. (C) 2000 Elsevier Science B.V. All rights reserved.