  We propose a directional switching effect in a metallic device. To such end
we exploit a graphene-based device with a three-terminal geometry in the
presence of a magnetic field. We show that unidirectional charge and valley
currents can be controlled by the Fermi energy and the magnetic field direction
in the active device. Interestingly, unidirectional transport of charge and
valley is generated between two-terminals at the same bias voltage.
Furthermore, we quantify the valley depolarization as a function of disorder
concentration. Our results open a way for active graphene-based valleytronics
devices.
