Two-step-wise interpretation of highly asymmetric, grazing angle (e,2e) on solids: A real momentum spectroscopy for surfaces and overlayers
- CNR-Istituto Metodologie Inorganiche e Plasmi, Area della Ricerca di Roma, Via Salaria km 29.300, 00016 Monterotondo (Italy)
- CNISM and Dipartimento di Fisica, Universita di Roma Tre, Via Vasca Navale 84, 00146 Roma (Italy)
- CNR-Istituto Sistemi Complessi, Area della Ricerca di Roma, Via Salaria km 29.300, 00016 Monterotondo (Italy)
This paper deals with the mechanism of grazing incidence (e,2e) events from surfaces. Two different approaches are considered. In both cases, elastic scattering with the crystal lattice assists the inelastic collision; these two steps are coupled either coherently or incoherently. Experimental evidence is given that the 'coherent' approach reproduces better the cross section dependence on momentum transfer in the specific case of asymmetric kinematics at moderate electron energies. This model has allowed us to map out the band dispersion of the outermost valence states of highly oriented pyrolytic graphite and to measure the momentum distribution of {pi}-electron states without invoking the contribution of reciprocal lattice vectors in the momentum conservation. Agreement between theory and experiment is satisfactory, though the presence of events where crystal momentum is reconstructed cannot be ruled out. These results, obtained with a significant reduction of the experiment duration by an implemented apparatus, show that reflection (e,2e) can be used to build up a momentum spectroscopy with high surface sensitivity.
- OSTI ID:
- 21143098
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 77, Issue 8; Other Information: DOI: 10.1103/PhysRevB.77.085116; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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