The intrinsic spin Hall effect

Summary form only given, as follows. A recent theory predicts that dissipationless spin currents can be induced purely by an electric field in conventional semiconductors. The dissipationless spin current is derived from a novel topological structure in momentum space, is independent of the sample disorder and leads to the intrinsic spin Hall effect. In hole doped semiconductors, with or without inversion symmetry breaking, there are no vertex corrections due to impurities scattering, and there are no extrinsic contributions to the spin Hall effect in the clean limit. The author analyzes a recent experiment on the spin Hall effect, and shows that it is consistent with the intrinsic nature of the effect. The author also shows that the spin Hall effect can be quantized in semiconductors with appropriate strain gradients, but in the absence of any external magnetic fields or the associated time reversal symmetry breaking.