Ab initio calculations for valley-selective dynamical Franz-Keldysh effect in monolayer WSe2

Transition metal dichalcogenide (TMD) monolayers have gained attention as potential spintronics and valleytronics materials due to their availability of spin and valley degrees of freedom as information carriers in devices. Specifically, monolayer TMDs possess direct bandgaps at the K and K’ valleys in the reciprocal space, where the band structure is spin-flipped and the interband transition at the K (K‘) valley is exclusively coupled to left (right) circularly polarized light. These characteristics make them suitable for ultrafast optical control of the valley degrees of freedom.