Professor Joel Moore
Department of Physics,
UC Berkeley and Materials Sciences Division, LBNL

The spin Hall effect and other examples of incoherent and coherent spin dynamics

It is now possible to use electron spin rather than electron charge to store, transport, and manipulate information, in increasing order of difficulty. Two important phenomena in spin transport are the spin Hall and spin drag effects; we review recent theoretical and experimental work on these effects in semiconductors, concentrating on a new mechanism to stabilize the spin Hall effect that is relevant to experiments on graphene. The spin Hall effect is fundamentally different from the ordinary (charge) Hall effect both in its symmetries (e.g., it does not require a magnetic field) and in the experimental conditions for its observation. Like thermal transport, spin transport probes quite different aspects of correlated electron systems than ordinary charge transport. With collective spin physics as motivation, we discuss in the last part of the talk how quantum information concepts are providing insight into and methodologies for quantum many-body physics. One result from this connection is an apparent extension of a famous theorem about critical entropies (the "c-theorem") to several classes of random quantum critical points.