I'll write more in the next day or two about what I think is a very exciting new result of ours. For now, I wanted to write a little about this paper:
arxiv:0801.4021, Frolov et al., Electrical generation of pure spin currents in a two-dimensional electron gas
For quite some time there has been a strong interest in using the spin degree of freedom of electrons for information processing. In some sense this is old news (see this past year's Nobel in physics), but the real trick is to see whether one can generate currents of only spin, rather than pushing whole, spin-polarized electrons through a circuit. In principle pure spin currents can be moved without dissipation, so if they can be generated and detected in a "nice" way, it may be possible to reduce the power required for certain computations. Of course, unlike charge, spin polarization is not conserved - spins generally prefer to relax back to an unpolarized state in the absence of big magnetic fields. This paper reports a way of generating spin currents that is quite clever - use quantum point contacts + spin-orbit scattering to generate an excess spin population in a region of 2d electron gas, and then the excess spin population diffuses away (without a net flow of charge). This paper also demonstrates that reducing the dimensionality of the system leads to an enhanced spin lifetime. It's a neat result and a very pretty experiment.