The electronic structure of ultrathin aluminum oxide film grown on FeAl(110): A photoemission spectroscopy

The electronic structure of the ultrathin aluminum oxide grown on the FeAl(110) surface has been investigated with angle-resolved photoemission spectroscopy. Previous scanning tunneling microscopy studies have revealed that exposing the clean FeAl(110) surface to 1000 1 of oxygen at 850°C forms a homogeneous hexagonal oxide film with a thickness of approximately 10 A. Core level photoemission spectra of FeAl constituents indicate that Al is the only metal species present in the oxide film. The measured band dispersion of the oxide thin film indicates a two dimensional electronic structure parallel to the plane of the thin film due to the limited thickness of the oxide thin films. The appearance of a peak in the anticipated band gap of the bulk oxide film suggests a unique electronic structure of the two dimensional oxide film. This latter observation is correlated with previous scanning tunneling microscopy results to elucidate the structure of the ultrathin alumina film grown on FeAl(110). © 2007 American Institute of Physics