A fundamental understanding of spin-dependent scattering and transport is central to "semiconductor spintronics." After a general introduction to key issues in this field, I will discuss recent experiments that examine the anomalous Hall effect in magnetically-doped 2D and 3D semiconductors [1,2]. This long-studied phenomenon has its origins in spin-dependent transport in the presence of a spin-orbit interaction and -- despite a long history of theoretical interest -- there is still ongoing debate about the interpretation of experimental observations. Our experiments allow us to systematically study the anomalous Hall effect in model systems, shedding new light into the mechanisms underlying the phenomenon.

1. J. Cummings et al, Phys. Rev. Lett. 96, 196404 (2006).

2. P. Mitra, N. Kumar and N. Samarth, arxiv:0808.2079.