Strain enhanced spin polarization in graphene with Rashba spin-orbit coupling and exchange effects

We investigate spin polarization and valley-dependent transport in bulk graphene in the presence of the exchange splitting field, the pseudo magnetic field, and Rashba spin-orbit coupling (SOC). It is demonstrated that Rashba SOC and the pseudo magnetic field cannot produce a spin polarization component perpendicular to the graphene sheet, but the exchange field can. However, the Rashba SOC leads to a finite in-plane spin polarization, which can be modulated by the pseudo magnetic field. Furthermore, it is also demonstrated that the valley polarization current cannot be produced in the considered system due to the mirror symmetry property of transmission probability for valley K and K′.