Very Efficient Spin Polarization Analysis (VESPA): New Exchange Scattering-based Setup for Spin-resolved ARPES at APE-NFFA Beamline at Elettra

Complete Photoemission Experiments, enabling to measure the full quantum set of the photoelectron final state, are in high demand for the study of materials and nanostructures whose properties are determined by strong electron and spin correlations. We report here on the implementation of the new spin polarimeter VESPA (Very Efficient Spin Polarization Analysis) at the APE-NFFA Beamline at Elettra that is based on the exchange coupling between the photoelectron spin and a ferromagnetic surface in a reflectometry setup. The system was designed to be integrated with a dedicated Scienta-Omicron DA30 electron energy analyzer allowing for two simultaneous reflectometry measurements, along perpendicular axes, that, after magnetization switching of the two targets allow to perform the 3D vectorial reconstruction of the spin polarization while operating the DA30 in high resolution mode. VESPA represents the very first installation for spin resolved ARPES (SPARPES) at the Elettra synchrotron in Trieste, and is being heavily exploited by SPARPES users since fall 2015.