Unoccupied electronic states of single-crystal graphite by angle-resolved ultraviolet inverse photoemission

Abstract

The unoccupied electronic states of a single crystal of natural graphite have been measured by angle-resolved inverse photoemission, with tunable photon energies in the range 14--26 eV. The normal-incidence data suggest that the interlayer band minimum probably lies at \ensuremath{\sim}5 eV above the Fermi level. An image-potential state is observed at 3.9 eV above the Fermi level along \ensuremath{\Gamma}A, existing in the gap below the interlayer state. The absence of turbostratic disorder has allowed unam- biguous determination of the distinct conduction-band dispersions in the two principal symmetry directions, \ensuremath{\Gamma}ALM and \ensuremath{\Gamma}AHK, up to 15 eV above the Fermi level.