Structure and magnetic properties of the Fe3O4(001) surface:: Ab initio studies -: art. no. 052401

First-principles calculations are employed to study four frequently proposed surface models for the Fe3O4(001) surface, i.e., the A-terminated surface (A model), the A-terminated surface with Fe vacancy (A-vac model), the B-terminated surface (B model), and the B-terminated surface with 0 vacancy (B-vac model). However, calculations have revealed that the outmost surface Fe atoms of the four surface models are all from the B-type layers, i.e., the A-site Fe atoms which were originally situated at the surface, according to the ideal bulk-terminated positions for the A and A-vac models moved underneath the next B-type layer following relaxation processes. Magnetic degradation of the four surface models is demonstrated to be mainly due to atomic relaxations. The half-metallic property remains in the B and B-vac models but destroyed in the A and A-vac models. The relative stability of the four surface models is also discussed.