POLARIZATION-DEPENDENT BORON AND NITROGEN K NEXAFS OF HEXAGONAL BN

The near-edge photoabsorption spectra of hexagonal boron nitride have been measured at the energies corresponding to boron and nitrogen K ed ges. Polarization of a synchrotron beam has been used to probe the loc al symmetry of empty states at each atomic site in this lamellar compo und. A large polarization dependence is observed up to 20 eV above eac h edge. Peak behaviors lead to the identification of pi and sigma* re sonances, as was already shown for graphite. But the striking result i s the observed differences between B and N spectra. The symmetry and e nergy dispersion of empty states at both sites will be discussed consi dering these experimental results.