Spin resolved photoemission spectroscopy on WSe2

The electronic structure of the layered semiconductor WSe2(0001) along Delt a is studied by spin resolved photoelectron spectroscopy using circularly p olarized radiation from the BESSY 6.5 m NIM. The experiments have been perf ormed in the highly symmetric setup of normal incidence and normal emission . The photon energies were varied between 8 eV and 17 eV. Our data give dir ect informations about the spin-orbit splittings Delta E-so in the valence bands: 0.45+/-0.1 eV, 0.32+/-0.1 eV. On the basis of a set of measured spec tra, a symmetry resolved bandmapping is performed for the valence bands, wh ich confirms a relativistic bandstructure calculation, The measured electro n spin polarizations agree with the group theoretical prediction and prove the symmetry labelling derived from a labelled nonrelativistic bandstructur e by using group theory to be correct. (C) 1999 Elsevier Science B.V. All r ights reserved.