Momentum distribution and valence-band reconstruction in graphite by grazing incidence (e,2e) spectroscopy

The capability of grazing angle (e,2e) experiments to map momentum distribution is demonstrated.: This is an application of reflection (e,2e) experiments as a unique twofold spectroscopy, binding energy and momentum distribution, for solid surfaces. The reported experiments have been performed on highly oriented pyrolytic graphite at about 300-eV incident energy, grazing angle, and for ejected electron energies ranging from 3.7 to 30 eV. These experiments, interpreted in the framework of the plane-wave impulse approximation, yield the binding energy vs momentum dispersion curves of valence electron states as well as the individual pi-state momentum density. Both results compare favorably with calculated graphite band structure. [S0163-1829(98)06404-2].