Control of Spin-Valley Current in Strain-Engineered Graphene Magnetic Junction

We investigate the spin-valley current in a strain-engineered graphene magnetic system, normal region (N)/strain region(S)/ferromagnetic region (F)/normal region (N) junction. Locally strained region S leads to valley-dependent current, and ferromagnetic region F leads to the spin-dependent current. We find that pure valley current can be created easily by applying the real-vector potential that is equal to the pseudo-vector potential caused by strains in the S-region. In this work, we focus on the spin current in each valley when exchange field is applied in the F-region, and find that the linear control of spin-valley polarization by gate potential is possible. It is also found that when the current is carried only by the carriers in one valley (pure valley current), pure spin-up current can be linearly altered to pure spin-down current by tuning the gate potential, in the case of very large-F-thickness junction. Our work is applicable for devising controllable spin-valley-current electronics circuits.