The capability of grazing-incidence (e,2e) spetroscopy to map the spectral momentum density rho(epsilon, q) of the valence electronic states in surfaces was demonstrated by a pioneering experiment in which both the band structure (binding energy, epsilon, versus momentum, q) and the momentum density, rho, were obtained [S, Rioual et al., Phys. Rev. B 57 (1998) 2545]. (e,2e) experiments reveal, in coincidence, after energy and angle selection, the two final electrons generated by the impact of a primary electron on the surface. The momentum resolution achieved by the first experiment was limited because of the integration over the wide solid angle accepted by the ejected-electrons analyzer. This limitation has been overcome in the present work by upgrading the ejected-electrons analyzer with a position-sensitive detector (PSD). The PSD allows us to measure the azimuth angle of the ejected electrons, and hence to collect in a parallel mode (e,2e) spectra that are fully differential in momentum. Preliminary data relative to the ionization of the pi-band of highly oriented pyrolitic graphite (HOPG) show that a momentum resolution better than 0.2 Angstrom(-1) has been achieved without degrading the overall spectrometer luminosity. (C) 2000 Elsevier Science B.V. All rights reserved.

Iacobucci, S., Ruocco, A., Rioual, S., Mastropietro, M., Stefan, G. (2000). Fully resolved kinematics of grazing-incidence (e,2e) experiments. SURFACE SCIENCE, 454, 1026-1030 [10.1016/S0039-6028(00)00129-1].

Fully resolved kinematics of grazing-incidence (e,2e) experiments

RUOCCO, Alessandro;
2000-01-01

Abstract

The capability of grazing-incidence (e,2e) spetroscopy to map the spectral momentum density rho(epsilon, q) of the valence electronic states in surfaces was demonstrated by a pioneering experiment in which both the band structure (binding energy, epsilon, versus momentum, q) and the momentum density, rho, were obtained [S, Rioual et al., Phys. Rev. B 57 (1998) 2545]. (e,2e) experiments reveal, in coincidence, after energy and angle selection, the two final electrons generated by the impact of a primary electron on the surface. The momentum resolution achieved by the first experiment was limited because of the integration over the wide solid angle accepted by the ejected-electrons analyzer. This limitation has been overcome in the present work by upgrading the ejected-electrons analyzer with a position-sensitive detector (PSD). The PSD allows us to measure the azimuth angle of the ejected electrons, and hence to collect in a parallel mode (e,2e) spectra that are fully differential in momentum. Preliminary data relative to the ionization of the pi-band of highly oriented pyrolitic graphite (HOPG) show that a momentum resolution better than 0.2 Angstrom(-1) has been achieved without degrading the overall spectrometer luminosity. (C) 2000 Elsevier Science B.V. All rights reserved.
2000
Iacobucci, S., Ruocco, A., Rioual, S., Mastropietro, M., Stefan, G. (2000). Fully resolved kinematics of grazing-incidence (e,2e) experiments. SURFACE SCIENCE, 454, 1026-1030 [10.1016/S0039-6028(00)00129-1].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/121905
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