Valley pump and beam splitting by a potential well on a monolayer hexagonal crystal*

We investigate the possibilities of realizing two distinct valleytronic functionalities in a single device by tuning an in‐situ controllable parameter, without changing the architecture of the system. We show that by means of a two‐dimenensional p‐n‐p junction or a lateral hetereojunction formed in a monolayer, two kinds of valleytronic functions can be realized by just changing the band alignment at the junction for both transition metal dichalcogenides and graphene. With shallow potential well, valley beam splitting is observed. Deepening the potential well by the applied gate voltages, we find highly polarized valley flow over a large range of out‐going angles. We further reveal that inter‐valley population transfer, whose importance can be adjusted by the gate potential, plays a crucial role in manifesting these interesting functionalities. These properties are maintained for armchair oriented junction interface as well as other chiral orientations.