Electronic Structure of Bismuth Ferrite and Hematite Single Crystals: X-Ray Photoelectron Study and Calculation

The X-ray photoelectron spectra of the inner levels and valence bands of the surfaces of BiFeO(3) and Fe(2)O(3) single crystals have been measured using X-ray photoelectron spectroscopy on an ESCALAB 250 X-ray photoelectron microprobe with monochromatization of X-ray radiation of the AlK(alpha) line. The ab initio calculations have been performed by the full-potential pseudopotential method in terms of the density functional theory (Quantum-Espresso program package). The band structure and the total and partial densities of states have been calculated for the BiFeO(3) and Fe(2)O(3) systems. A comparison of the theoretical and experimental results has demonstrated good agreement between theory and experiment.