Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 62: Posters: Surface Reactions and Dynamics, Nanostructures
O 62.16: Poster
Mittwoch, 2. April 2014, 17:30–21:00, P1
Spin Effects in Ultrafast Charge Transfer Measurements on Ar/Co Interfaces using a TOF-Mott-Polarimeter — •Tobias Sundermann1, Norbert Müller1, Ulrich Heinzmann1, Johannes Bauer2, Runyuan Han2, Peter Feulner2, and Wilfried Wurth3 — 1Molecular and Surface Physics, Bielefeld University — 2Physik-Department E20, TU München — 3Physik-Department, University of Hamburg
Using the principle of the core hole clock method [1] the spin dependent charge transfer is studied from resonantly excited physisorbed Ar atoms into an in plane magnetized Co adlayer on W(110). For exciting the Ar 2p3/2 → 4s resonance circularly as well as linearly polarized synchrotron radiation of energy hν = 244.55 eV is used (BESSY beamline UE56/II PGM2, single bunch mode). Emitted electrons are energy and spin analyzed by means of a TOF spectrometer followed by a spherical Mott polarimeter [2] operated in retarding mode at 45 keV scattering energy. Excitation by circularly polarized radiation results in a spin polarization up to 35%± 5% of the Auger electrons following the decay of the excited oriented Ar 2p3/2 holes. With excitation by linearly polarized radiation smaller spin polarization effects appear for autoionization emission channels. These effects result from a spin dependent charge transfer from excited unpolarized Ar 4s states to empty Co conduction band states with minority spin preferred.
[1] D. Menzel, Chem. Soc. Rev., 37 (2008)
[2] G. Snell et al., Phys. Rev. Lett. 76, 3923 (1996)