Observation of Hidden Orbital Pseudospin Textures using new Physical Observables.
ARPES and momentum microscopy are the basis for a novel approach in surface science characterization.
Looking at a new physical observable, the so called time-reversal dichroism in photoelectron angular distributions (TRDAD), the S. Baulieu team from the Ernstorfer Group at the FHI Berlin, observed exciting effects on a TMDC sample. The hidden orbital pseudospin, e.g. the alternating local spin polarization and orbital texture of neighboring layers of 2H-WSe2, was observed while rotating the sample by 60° in front of the ToF Momentum Microscope METIS 1000. Here the TRDAD observes the modulation of the photoemission intensity upon time reversal change of the lattice symmetry of the sample, being sensitive to the orbital pseudospin texture. The authors compare their new observable to theoretical calculations, presenting the robustness of their considerations.