Fe t2g band dispersion and spin polarization in thin films of Fe3O4(0 0 1)/MgO(0 0 1): Half-metallicity of magnetite revisited

We have performed angle- and spin-resolved photoemission measurements on Fe3O4(0 0 1)/MgO(0 0 1). Despite intrinsic electron-lattice (polaron) interaction a Fe t2g band dispersion is observed, as well as a Fermi surface. The states close to the Fermi level show a spin polarization up to -72% as measured with a 4.65 eV laser light. All the data can be simulated starting from GGA+U bulk band-structure calculations and taking into account the polaron and initial-state lifetime broadening involved in the photoemission process. This conciliates the electronic structure of Fe3O4 with a band model and confirms the half-metallic nature of Fe3O4.