The photoelectron bandstructure of molybdenum disulphide

An experimental electronic bandstructure of molybdenum disulphide has been determined from angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) measurements: polar-angle-dependent ARUPS at a photon energy of 21.2 eV allows the authors to obtain an approximate plot of dispersion parallel to the basal face while photon-energy-dependent ARUPS at normal emission gives a plot of dispersion perpendicular to this face. The experimental bandstructure is compared with three calculations and, while there is a general agreement, specific aspects are better reproduced when there is self-consistency in the calculations. An analysis difficulty reported earlier for polar angle ARUPS for this material can now be understood as arising from incorrect labelling of symmetry directions in the experiment.