Switchable Valley Injection Into Graphene

The generation and control of the valley-polarized current play the key roles in valleytronics applications, but still remain as tough challenges. We propose a general idea of switchable valley injection, and predict theoretically that a ferromagnet-covered graphene junction would take the role of a valley injector, whose ON/OFF state can be easily switched only by changing the magnetic direction. This scheme can be extended to other two-dimensional crystals and may lead to an alternative path for valleytronic practical applications.