Synchrotron-radiation-excited angle-resolved photoemission from single-crystal graphite

Synchrotron-radiation-excited angle-resolved photoemission from a single crystal of natural graphite is reported. Using photon energies between 20 and 65 eV, all the valence-band dispersions and critical-point binding energies have been determined. The photon-energy dependence of normal emission spectra yielded a π-band $k_z$ dispersion of ∼1 eV, less than theoretically predicted. Distinct secondary-electron features in the spectra allow determination of the dispersion of certain conduction bands lying up to 20 eV above the Fermi level. Such high-energy conduction bands have not been observed by inverse photoemission.