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.