Controllable valley polarization using graphene multiple topological line defects

Abstract

The electron transport of different conical valleys is investigated in graphene with extended line defects. Intriguingly, the electron with a definite incident angle can be completely modulated into one conical valley by a resonator which consists of several paralleling line defects. The related incident angle can be controlled easily by tuning the parameters of the resonator. Therefore, a controllable $100%$ valley polarization, as well as the detection of the valley polarization, can be realized conveniently by tuning the number of line defects and the distance between two nearest-neighboring line defects. This fascinating finding opens a way to realize the valley polarization by line defects. With the advancement of experimental technologies, this resonator is promising to be realized and thus plays a key role in graphene valleytronics.