Quantum rings as electron spin beam splitters
  Quantum interference and spin-orbit interaction in a one-dimensional mesoscopic semiconductor ring with one input and two output leads can act as a spin beam splitter. Different polarization can be achieved in the two output channels from an originally totally unpolarized incoming spin state, very much like in a Stern-Gerlach apparatus. We determine the relevant parameters such that the device has unit efficiency. 
Peter Foldi, Orsolya Kalman, Mihaly G. Benedict, F. M. Peeters