Untitled - IAP/TU Wien - Technische Universität Wien
Untitled - IAP/TU Wien - Technische Universität Wien
Untitled - IAP/TU Wien - Technische Universität Wien
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71st IUVSTA Workshop<br />
Plasmon resonant (e,2e) spectroscopy<br />
A. Ruocco a , W. S.M. Werner b , M.I. Trioni c , F. Offi a , S. Iacobucci d , W. Smekal b<br />
G. Di Filippo e and G. Stefani a<br />
a Dipartimento di Scienze <br />
b , Vienna University of Technology, Vienna,<br />
Austria<br />
c CNR, Istituto di Scienze e Tecnologie Molecolari (ISTM), Milan Italy<br />
d IFN-<br />
e <br />
The (e,2e) process has been largely used to investigate ionization mechanisms<br />
and electronic structure in atoms, molecules and solids. In solids, one of the<br />
most efficient channels of electron impact energy transfer is excitation of<br />
volume or surface plasmons (collective excitations of the electron gas). Two<br />
main plasmon decay mechanisms have been foreseen: the excitation of nearly<br />
free secondary electrons and the excitation of pair of correlated free electrons 1 .<br />
In competition with these two channels, the ejection of a secondary electron due<br />
to direct scattering within a medium described by its inverse dielectric function<br />
has been proposed 2 .<br />
To establish the relative relevance of these secondary electron generation<br />
channels is of importance in many branches of fundamental and applied<br />
science.<br />
In this paper will be reviewed (e,2e) plasmon assisted experiments performed<br />
on Al and Be clean surfaces. The early experiment on Al 3 , performed at 100eV<br />
incident energy, proposes that observed secondary electrons are emitted via a<br />
mechanism similar to photoemission with plasmon decay playing the role of<br />
photon absorption. The experiment performed always on Al at 500 eV 4 proves<br />
that surface plasmon decay accounts for roughly a quarter of the secondary<br />
electron spectrum. More recent experiment on Be 5 point to plasmon resonant<br />
(e,2e) processes as a relevant channel for secondary electron generation and<br />
for building a resonant momentum spectroscopy.<br />
1 G.A. Bocan and J.E. Miraglia, Phys Rev. A 71, 024901 (2005) and reference therein.<br />
2 K.A. Kouzakov and J. Berakdar, Phys. Rev. A 85, 022901 (2012)<br />
3 W.S.M. Werner, et al. Phys. Rev. B 78, 233403 (2008)<br />
4 W.S.M. Werner, et al. Appl. Phys. Lett. 99, 184102 (2011)<br />
5 A. Ruocco et al. private communication (2012)<br />
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