Band Gap and Electronic Structure of an Epitaxial, Semiconducting Cr0.80Al0.20 Thin Film

Cr1-xAlx exhibits semiconducting behavior for x = 0.15-0.26. This Letter uses hard x-ray photoemission spectroscopy and density functional theory to further understand the semiconducting behavior. Photoemission measurements of an epitaxial Cr0.80Al0.20 thin film show several features in the valence band region, including a gap at the Fermi energy (E-F) for which the valence band edge is 95 +/- 14 meV below E-F. Theory agrees well with the valence band measurements, and shows an incomplete gap at E-F due to the hole band at M shifting almost below E-F.