Inter- and Intralayer Excitonic Spectrum of MoSe2/WSe2 Heterostructure

Transition metal dichalcogenide heterostructures which are built from atomically thin layers of MX2 crystals, enable the formation of excitons composed of electrons and holes in distinct layers. In the following work, we describe the electronic and excitonic properties of MoSe2/WSe2 heterostructure using a combination of the ab initio based effective mass approximation and the Bethe-Salpeter theory. First, we analyse electronic structure and Kohn-Sham wavefunctions that allow for spin/layer detection. In the next step, we construct an effective mass model for 8 bands around K valley consistent with experimental bandgaps. Using approximate inter- and intralayer screening we calculate the fine structure of inter- and intralayer excitons, predicting rich optical spectrum of interlayer A/B, spin bright/dark and ground/excited state with zero total momentum.