Credit: Chris Jozwiak/Berkeley Lab
This rendering shows a "ball-and-stick" representation of the atomic structure of a 2-D single crystalline layer of tungsten disulfide (blue and yellow) on top of layers of 2-D boron nitride (silver and gold). On top of these is a representation of the structure of electronic energy levels, or valence bands, within the tungsten disulfide, and the increased splitting between the two valence bands observed using an x-ray technique at the MAESTRO beamline. The experiments suggest the effect could be due to "trions," made up of two holes and an electron in the bands, depicted as clear and dark spheres. The background is raw data of the electronic structure of the tungsten disulfide, as measured in the experiment.