Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 4: Surface Magnetism: Atoms and Molecules

O 4.2: Vortrag

Montag, 7. März 2016, 10:45–11:00, S052

Calibration of highly efficient FeO-based spin polarization detector — •Pika Gospodaric, Ewa Mlynczak, Markus Eschbach, Mathias Gehlmann, Sven Döring, Lukasz Plucinski, and Claus Michael Schneider — Peter Grünberg Institut PGI-6, Forschungszentrum Jülich, 52425 Jülich, Germany

A recently developed FeO-based spin polarization detector (1) was adapted to a high-resolution hemispherical MBS A-1 electron analyzer to study the spin degree of freedom in the electronic band structure of spintronic materials with spin- and angle-resolved photoemission spectroscopy (spinARPES). The operation of the polarimeter is based on the exchange scattering of electrons from an oxidized Fe(100) film, which can be magnetized in four orthogonal in-plane directions. Our setup employs a 90^∘ deflector, which allows probing one of the in-plane and the out-of-plane spin components. In this talk, performance calibration tests of the system using the Rashba spin-orbit split surface states of the single crystal Au(111) and various topological insulator thin films will be presented. At optimized scattering energy the asymmetry function reaches 30% and the reflectivity up to 10%, which results in a 20-40 times higher figure of merit compared to the conventional Mott spin detectors. Experiments were performed using an unpolarized noble-gas discharge lamp and a laser-based 6 eV photon source with light polarization control. The high energy and angular resolution of the spinARPES spectra clearly distinguishes the two spin polarized branches of the Au(111) surface state.

(1) M. Escher et al., e-J. Surf. Sci. Nanotech. Vol. 9 (2011)