Measuring spin-resolved density of states of solid surfaces is the key to access the magnetic properties of low dimensional systems as well as to investigate the band structure spin texture of complex materials where the electronic properties arise from spin-orbit coupling effects, such as the topological insulators.
We designed and developed the 3D vectorial spin polarimeter based on the very low-energy electron diffraction (VLEED) within the NFFA-Trieste facility project. The VESPA spin polarimeters, which exploit the exchange coupling between between the photoelectron spin and a ferromagnetic surface in a reflectometry setup, are combined with a state of art ARPES analyser. The whole system is installed on the Low-Energy branch of the Advance Photoelectric Effect beamline (APE-LE), working with variably polarized synchrotron radiation tunable in 10-100 eV range from the Elettra storage ring at Trieste. The detector performances were tested on the small Rashba splitting of the Au(111) surface state and the results show the system is well-performing and competitive at international level, making up an advanced system for spin and angular-resolved photoemission.
Bigi C. et al (2017). J. Synchrotron Rad. 24 in press