Angle-resolved photoemission study of Fe3O4(0?0?1) films across Verwey transition

The valence band structure of well-ordered Fe3O4(0 0 1) films was investigated in situ by angle-resolved photoemission spectroscopy (ARPES) at room temperature (RT) and 90 K. A band gap of about 70 meV below the Fermi level (EF) can be observed at 90 K, suggesting a 'metal–insulator' transition. With temperature reduced from RT to 90 K, O 2p-derived features shown in ARPES spectra change substantially. Meanwhile, the feature near EF of the Fe3O4(0 0 1) film at 90 K becomes about 0.1 eV deeper than that at RT. The results are compared with recent theoretical studies.