Electron supersurface scattering on polycrystalline Au

Supersurface electron scattering, i.e., electron energy losses and associated deflections in vacuum above the surface of a medium, is shown to contribute significantly to electron spectra. We have obtained experimental verification (in absolute units) of theoretical predictions that the angular distribution of the supersurface backscattering probability exhibits strong oscillations which are anticorrelated with the generalized Ramsauer-Townsend minima in the backscattering probability. We have investigated 500-eV electron backscattering from an Au surface for an incidence angle of 70° and scattering angles between 37° and 165°. After removing the contribution of supersurface scattering from the experimental data, the resulting angular and energy distribution agrees with the Landau-Goudsmit-Saunderson (LGS) theory, which was proposed about 60 years ago, while the raw data are anticorrelated with LGS theory. This result implies that supersurface scattering is an essential phenomenon for quantitative understanding of electron spectra.

Combined energy and angular spectrum of 500 eV electrons backscattered from an Au surface. The elastic peak has been removed from all data sets to improve contrast. (a) As measured. (b) Theoretical results according to the Landau-Goudsmit-Saunderson theory. (c) Experimental data after elimination of the supersurface scattering contribution

¹Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstraße 8–10, A 1040 Vienna, Austria
²Université Libre de Bruxelles, Service de Métrologie Nucléaire (CP 165/84), 50 avenue F. D. Roosevelt, B-1050 Brussels, Belgium
³Institut fűr Theoretische Physik, J.W.Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
⁴Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Na Slovance 2, 182 21 Prague 8, Czech Republic