Single-particle gap above the Verwey transition in Fe3O4

The Verwey transition in magnetite, Fe3O4, has been studied using temperature-dependent high-resolution photoemission spectroscopy. On heating through the transition temperature TV the band gap is not collapsed, but is merely reduced by ∼50 meV, showing that a metal-insulator transition does not occur. The change in the gap is perfectly consistent with the two orders of magnitude conductivity jump at TV. Thus even above TV short-range charge ordering rather than site equivalency dominates the single-particle excitations and the electrical properties. We also point out important implications for efforts to model the electrical transport above TV