Münster 1999 – wissenschaftliches Programm

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O: Oberflächenphysik

O 11: Poster (I)

O 11.59: Poster

Montag, 22. März 1999, 19:30–22:30, Aula

k-resolved (e,2e) spectroscopy of solid surfaces — •O. Artamonov, S. Samarin, H. Schwabe, and J. Kirschner — MPI f/"ur Mikrostrukturphysik, Weinberg 2, D-06120 Halle

In k-resolved (e,2e) electron spectroscopy we detect two outgoing

electrons after scattering of the low energy primary electron on

the solid surface. The time-of-flight technique with the pulsed

primary electron beam and position sensitive detectors allow us

to measure directly intrinsic velocity of outgoing electrons as

vectors. In the experiment we store six components of the electron

momenta of each single scattering event in the list-mode. The sum

momentum of the scattered electron pair is defined by the valence

electron k-vector, whereas the difference of scattered electron

momenta defines the internal freedom of the electron pair and

reflects the scattering dynamics of the primary electron on the

valence one. The measured pair distribution in the momentum space

is transformed in the two-dimensional density versus the parallel

to the surface components of the quasi-wave vector of the valence

electrons. The measurements on the W(100) and the Fe(110) single

crystals with the primary electron energy of 18 - 50 eV demonstrate

that in the same experimental setting we can scan the valence electron

states in the considerable part of the Brillouin zone.