We present a proposal for an adiabatic quantum pump based on a graphene monolayer patterned by electrostatic gates and operated in the low-energy Dirac regime. The setup under investigation works in the presence of inhomogeneous spin-orbit interactions of intrinsic- and Rashba-type and allows to generate spin polarized coherent currents. A local spin polarized current is induced by the pumping mechanism assisted by the spin-double refraction phenomenon.
The symmetry properties of the charge/spin currents can be understood by looking at the symmetry properties of the system Hamiltonian (1) with respect to the operator where transforms . (Refs. 8 and 19) This operator describes the exchange of spin-state and injection direction . It commutes with the total system Hamiltonian (1) allowing, therefore, for a common basis of eigenstates.