Europhys. Lett.
Volume 75, Number 6, September 2006
Page(s) 964 - 970
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 09 August 2006
Europhys. Lett., 75 (6), pp. 964-970 (2006)
DOI: 10.1209/epl/i2006-10192-7

Fermi momentum above metal surface from electrons ejected by impact of $\chem{He}$ atoms

H. Winter1, S. Lederer1 and HP. Winter2

1  Institut für Physik, Humboldt Universität zu Berlin Brook-Taylor-Str. 6, D-12489 Berlin-Adlershof, Germany
2  Institut für Allgemeine Physik, Technische Universität Wien Wiedner Hauptstr. 6-10, A-1040 Wien, Austria

received 18 May 2006; accepted in final form 19 July 2006
published online 9 August 2006

Kinetic emission (KE) of electrons near its threshold is studied for grazing impact of keV He atoms on flat and clean Al(111), Al(110), and Cu(111) surfaces. We observe a defined dependence of the KE threshold behaviour on the scattering conditions. The data are analyzed in the framework of a classical model for electron emission based on momentum transfer in binary encounters between atomic projectiles and conduction electrons of the metal target. From the impact velocity dependence of KE yields near threshold we obtain information on momenta of Fermi electrons as a function of distance from the surface and on the corresponding electronic surface potential.

79.20.Rf - Atomic, molecular, and ion beam impact and interactions with surfaces.
79.60.Bm - Clean metal, semiconductor, and insulator surfaces.
73.20.-r - Electron states at surfaces and interfaces.

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