Photon energy dependence of graphite valence band photoelectron intensity

We have measured two-dimensional photoelectron spectra of graphite with various photon energies. We investigated the photon energy dependence of the valence band dispersions of graphite at vicinity of Fermi level which appear at Brillouin zone (BZ) corners. We found that the photoelectron intensities of the Fermi surfaces were, however, very different even when the photon energies are selected to see the same symmetry planes of BZ. This intensity difference of the Fermi surfaces is well reproduced by considering the “photoemission structure factor” for three-dimensional nature of graphite.