Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 43: Clean surfaces III
O 43.10: Talk
Wednesday, March 28, 2012, 12:45–13:00, MA 043
Dichroism in double photoemission from a Cu surface — Zheng Wei1, •Frank O. Schumann1, Gianluca Difilippo2, Giovanni Stefani2, and Jürgen Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany — 2Dipartimento di Fisica, Università Roma Tre, Rome, Italy
We performed a double photoemission (DPE) experiment with circular polarized light on a Cu(001) surface. The
photon energy was chosen to be 125 eV leading to comparable kinetic energies of the 3p photo electron and related Auger
electron. We find that the coincidence spectra display circular dichroism while the singles spectra are helicity
independent. Usually the emergence of an Auger electron is explained via a two-step process in which the relaxation leading
to the Auger emission is preceded by the emission of a photoelectron. This is at odds with a continuous energy sharing [1]
and the observation of dichroism in the coincidence spectra only. Our observation can only be explained within a single-step
process.