Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 110: Surface Magnetism
O 110.4: Talk
Friday, March 22, 2024, 11:15–11:30, MA 144
Magnetic dichroism and spin polarization in threshold photoemission — •Frank O. Schumann1, Jürgen Henk2, Friederike Elisa Wührl2, David Huber2, and Wolf Widdra2 — 1Max-Planck Institut für Mikrostrukturphysik, Halle, Germany — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Germany
An emitted photoelectron can be analyzed with respect to energy, emission direction and spin polarization. The latter parameter is of particular interest for magnetic materials. The photoemission intensity depends on the polarization state of the light and magnetization direction leading to magnetic dichroism usually expressed as asymmetry. This can be used for magnetic contrast in domain imaging. For a microscopic description of spin polarization and magnetic dichroism it is vital to include both the spin-orbit and exchange interaction on an equal footing. We performed an appropriate one-step photoemission calculation for threshold photoemission from a Fe(100) surface. We found good agreement to the experimental magnetic dichroism data obtained with a photon energy of 5.2 eV. Apart from the intensity we obtain the theoretical spin polarization spectra. These are decomposed into an exchange and spin-orbit part. We find a sizable spin-orbit polarization and observe a resemblance to the asymmetry spectrum. We bring this into relation to analytical work, which demonstrated a connection between magnetic dichroism and the spin-orbit polarization in the limit of vanishing exchange interaction [1].
Keywords: Photoemission; magnetic dichroism