Valence-band maximum in the layered semiconductor WSe2: Application of constant-energy contour mapping by photoemission

Angular-resolved photoemission data and a full-potential fully relativistic density-functional calculation on the electronic band structure of the layered semiconductor WSe2 consistently show that the valence-band maximum is located at the sixfold-degenerate K point of the Brillouin zone and not at its center, as earlier calculations have predicted. By mapping out constant energy contours with photoemission spectroscopy, the k space location of the valence-band maximum can be visualized in a very instructive way, demonstrating the potential of this spectroscopic technique also for semiconductors.