Probing buried interface band dispersion of a MgO/Fe heterostructure with hard X-ray angle-resolved photoemission

Abstract

Interface band dispersion of a MgO(2 nm)/Fe(50 nm) heterostructure was detected by hard X-ray angle-resolved photoemission spectroscopy (HARPES) with the excitation photon energy of 3.29 keV by utilizing X-ray total reflection (TR). By subtracting bulk-sensitive band dispersion of the buried Fe(001) obtained by HARPES in the non-TR condition from near-interface-sensitive Fe(001) band dispersion obtained by TR-HARPES, the band-folding of Fe and the O 2p -Fe 3d hybridization at the heterointerface were clearly unveiled. These results suggest that HARPES can probe not only bulk band but also buried interface band of heterojunctions.