Comment on Theory of spin Hall effect

Chudnovsky recently proposed (arXiv: 0709.0725) a beautifully simple mechanism for the intrinsic spin Hall effect involving an extension of the Drude model. We point out that an equivalent proposal was made by us in an alternative treatment of the problem in Phys.Rev. B60, 14787 (1999) (arXiv:cond-mat/9910408, reaching identical conclusions. The coincidence of both approaches supports their physical validity. The mechanism applies to the spin Hall effect in all metals and semiconductors and to the anomalous Hall effect in all ferromagnetic metals and semiconductors.