Bulk band dispersion in Ti2O3 and V2O3

We report here a comprehensive study of the bulk electronic structure of single-crystal Ti2O3 and V2O3 using both angle-integrated and angle-resolved photoemission and synchrotron radiation. The electronic structure of these materials is of particular interest because of the metal-insulator transitions which they undergo. Slight (<0.4 eV) dispersion of the cation 3d bands is observed in both materials, supporting a band model for their electronic structure. Large discrepancies are observed between the measured band dispersion and published calculations for both materials. The O 2p emission is too broad to permit extraction of unambiguous band dispersions. Resonant photoemission is observed from cation 3d states in both Ti2O3 and V2O3 as the photon energy is swept through the cation 3p→3d optical-absorption edge. A valence-band satellite is resolved in the angle-integrated photoemission spectra from V2O3; resolving this feature shows that the actual width of the O 2p band in V2O3 is almost 2.5 eV narrower than previous studies indicated