Looking for the Spin Hall Effect in all the Wrong Places – Nitin Samarth

Date: Mon. October 1st, 2007, 12:30 pm-1:30 pm
Location: Rockefeller 221

The spin and anomalous Hall effects are related phenomena that arise from spin-dependent electrical transport in solids in the presence of spin-orbit coupling. Conventional wisdom has motivated many experimental studies of these effects in systems where spin-orbit coupling effects are inherently strong. I will describe two recent experiments on systems with manifestly weak spin-orbit coupling that suggest a need to cast a wider net in explorations of the spin and anomalous Hall effects. Our studies surprisingly reveal: a. An electrically-tunable anomalous Hall effect in paramagnetic 2DEGs formed in a magnetically-dilute, wide bandgap semiconductor quantum well; [1] b. A room temperature spin Hall effect in an n-doped wide bandgap semiconductor. [2]
[1] J. Cumings et al, Phys. Rev. Lett. 96, art. no. 196404 (2006).
[2] N. Stern et al., Phys. Rev. Lett. 97, art. no. 126603 (2006).