Coupled spin-charge dynamics in semiconductors: from Coulomb drag to spin Hall effect

by Giovanni Vignale (University of Missouri-Columbia)

Tuesday 8 Oct 2013, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

The recently acquired capability to excite transient spin and electron-hole density gratings in semiconductors quantum wells and monitor their evolution in real time opens new avenues to the study of coupled spin-charge dynamics of electrons in semiconductors. In this talk I describe some of the physical effects that have been recently observed by this technique: the spin Coulomb drag, the electron-hole Coulomb drag, and the anomalous drift and diffusion caused by spin-orbit interactions. I then discuss a recent theoretical prediction that an electric field parallel to the wavefronts of an electron-hole grating in a GaAs quantum well generates, via the electronic spin Hall effect, a spin grating. A detailed study of the coupled spin-charge dynamics for quantum wells grown in different directions reveals rich features, including the possibility of generating a helical spin grating from a de! nsity grating.