Twist angle dependent interlayer transfer of valley polarization from excitons to free charge carriers in WSe2/MoSe2 heterobilayers

Abstract Transition metal dichalcogenides (TMDs) have attracted much attention in the fields of valley- and spintronics due to their property forming valley-polarized excitons when illuminated by circularly polarized light. In TMD-heterostructures it was shown that these electron-hole pairs can scatter into interlayer exciton states, which exhibit long lifetimes a twist-angle dependence. However, question how create valley polarization free charge carriers heterostructures after selective optical excitation is unexplored, despite its relevance for opto-electronic devices. Here, we identify an transfer mechanism twisted WSe 2 /MoSe heterobilayers transfers from MoSe with up 12 ns. This most efficient at large twist angles, whereas are surprisingly short small occurrence excitons.