Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Jan. 10, 2017 at 12:15 p.m. in Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude)Prof. Dr. Hans-Joachim Elmers
Institut für Physik, KOMET 5
elmers@uni-mainz.de
Prof. Dr. H. J. Elmers
Photoemission spectroscopy has become the key technique for the investigation of elec- tronic properties of promising materials such as Heusler compounds, Weyl systems, ma- terials exhibiting a strong Rashba effect, topological insulators or hybrid metal-organic interfaces. During the last decade photoemission spectroscopy without spin resolution enjoyed a considerable increase in performance due to parallel image detection while the spin polarization analysis of a given electron beam remained time consuming. Since poten- tial candidates for spintronic applications such as metal-organic interfaces tend to degrade within a short period, a massive reduction of spin-resolved data acquisition time is crucial.
A newly developed high-performance imaging spin filter system based on a large Ir(001) scattering crystal tackles this issue by enhancing the measurement efficiency. An increase of the effective figure of merit by a factor of over 10^3 in contrast to standard single-channel detectors is presented together with a detailed characterization of the experimental setup.
Furthermore, the spectrometer resolution, spin filter preparation and lifetime are reviewed.
An energy and angular resolution of 27 meV and 0.23 ◦ has been determined for an en- ergy and angular acceptance of 1.5 eV and ±10 ◦ . The spin filter efficiency is analyzed by mapping a broad range of scattering energy and azimuthal angle. If the scattering plane coincides with a mirror plane of the crystal, the spin filter is only sensitive to the component of the spin vector perpendicular to the scattering plane. A scattering plane that does not coincide with a crystal mirror plane yields a high sensitivity to spin vector components that are parallel to the scattering plane. A spin rotator element enables the independent determination of the two in-plane components of the spin vector. By combining three or six scattering conditions a vectorial spin analysis becomes possible for both, magnetic and non-magnetic samples.