Photoemission spectroscopy has become the key technology for the investigation of electronic properties of promising materials such as Heusler compounds, Weyl systems, materials with Rashba effect, topological insulators or metal-organic interfaces. In recent years, the efficiency of photoemission spectroscopy has been greatly enhanced by introducing parallel imaging. However, the analysis of the spin polarization remained time-consuming. Since potentially suitable materials for spintronic applications such as metal-organic interfaces tend to deteriorate rapidly, a significant reduction in the duration of spin-resolved data is necessary.
A newly developed and powerful imaging spin filter, based on a large Ir (001) scattering crystal, addresses this problem by increasing the measuring efficiency. An increase of the effective figure of merit by a factor of more than 10³ in contrast to conventional single-channel detectors is achieved. In particular, the spectrometer resolution is determined in the energy and impulse space. The energy and angle resolution is 27 meV or 0.23 ° for an energy and angular acceptance of 1.5 eV or +/- 10 °. The spin filter efficiency is mapped and analyzed over large energy and angular ranges. Under ideal conditions, a Sherman function of up to 0.44 is measured. If the scattering plane coincides with a mirroring plane of the crystal, the spin filter is only sensitive to the component of the spin vector perpendicular to the scatter plane. Plots which do not coincide with a mirroring plane result in a high sensitivity for components of the spin vector parallel to the scattering plane. A spin rotator element allows 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 magnetic and non-magnetic samples.