Parametric quantum spin pump
  We investigate a non-adiabatic parametric quantum pump consists of a nonmagnetic scattering region connected by two ferromagnetic leads. The presence of ferromagnetic leads allows electrons with different spins to experience different potential landscape. Using this effect we propose a quantum spin pump that drives spin-up electrons to flow in one direction and spin-down electrons to flow in opposite direction. As a result, the spin pump can deliver a spin current with vanishing charge current. 
Wei Zheng, Junling Wu, Baigeng Wang, Jian Wang, Qingfeng Sun, and Hong   Guo