Manuel Gonçalves (*)
Moritz
Trautvetter(+)
Oliver
Dubbers(+)
Sebastian Fricker(+)
Alfred Plettl(+)
Othmar
Marti(*)
Paul Ziemann(+)
(*) Department of Experimental Physics
(+) Department of Solid State Physics
University of Ulm
D-89069 Ulm, Germany