Theory of spin-polarized transport in semiconductor heterojunctions:   Proposal for spin injection and detection in silicon
  Spin injection and detection in silicon is a difficult problem, in part because the weak spin-orbit coupling and indirect gap preclude using standard optical techniques. We propose two ways to overcome this difficulty, and illustrate their operation by developing a model for spin-polarized transport across a heterojunction. We find that equilibrium spin polarization of holes leads to a strong modification of the spin and charge dynamics of electrons, and we show how the symmetry properties of the charge current can be exploited to detect spin injection in silicon using currently available techniques. 
Igor Zutic, Jaroslav Fabian, and Steven C. Erwin