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