Current-induced spin polarization and spin-orbit torque in graphene

Authors:

• Anna Dyrdał,
• Józef Barnaś

Abstract

Using the Green-function formalism, we calculate a current-induced spin polarization of weakly magnetized graphene with Rashba spin-orbit interaction. In a general case, all components of the current-induced spin polarization are nonzero, contrary to the nonmagnetic limit, where the only nonvanishing component of spin polarization is that in the graphene plane and normal to the electric field. When the induced spin polarization is exchange coupled to the magnetization, it exerts a spin-orbit torque on the latter. Using the Green-function method, we have derived some analytical formulas for the spin polarization and also determined the corresponding spin-orbit torque components. The analytical results are compared with those obtained numerically. Vertex corrections due to scattering on randomly distributed impurities are also calculated and shown to enhance the spin polarization calculated in the bare bubble approximation.