Spin currents in the Rashba model in the presence of non-uniform fields
  Spin currents in a two dimensional electron gas with Rashba-type spin orbit coupling are derived from a spin connection. Using a functional integral method, we recover the result derived by Sinova {\em et al.}$[ \mathrm{Phys.Rev. Lett.   92, 126603 (2004)}]$ for a uniform electric field and in the absence of impurities. We extend this result to inhomogeneous electric and magnetic fields. We find that non-uniform magnetic fields can give rise to spin currents that are independent of the Rashba coupling and hence are less susceptible to impurities than in the case of uniform electric fields. 
A. Rebei O. Heinonen