  The electronic structure of AlN in wurtzite and zinc-blende phases is studied
experimentally and theoretically. By using x-ray emission spectroscopy, the Al
3p, Al 3s and N 2p spectral densities are obtained. The corresponding local and
partial theoretical densities of states (DOS), as well as the total DOS and the
band structure, are calculated by using the full potential linearized augmented
plane wave method, within the framework of the density functional theory. There
is a relatively good agreement between the experimental spectra and the
theoretical DOS, showing a large hybridization of the valence states all along
the valence band. The discrepancies between the experimental and theoretical
DOS, appearing towards the high binding energies, are ascribed to an
underestimation of the valence band width in the calculations. Differences
between the wurtzite and zinc-blende phases are small and reflect the slight
variations between the atomic arrangements of both phases.
