Spin Transport in Ferromagnet/III–V Semiconductor Heterostructures
This chapter provides a review of a sequence of experiments that have advanced the understanding of spin transport in semiconductors through their sensitivity to electron spin dynamics. It focuses on the progression of experiments leading up to the demonstration of an III–V based lateral spin valve, some discussion of more developments as well as additional references are included in the revision. The processes of electrical spin injection, transport, and detection in nonmagnetic semiconductors are inherently nonequilibrium phenomena. In spite of the rapid refinement of spin-light-emitting diode and the achievement of correspondingly high spin injection efficiencies, the appropriate modification of the devices for lateral transport experiments was not immediately apparent. The overall phenomenology of the non-local measurements is in general agreement with expectations based on the drift-diffusion model for spin transport in the semiconductor. In combination with ordinary diffusive transport theory, knowledge of the relevant spin lifetimes allows to identify the critical length scales for a spin transport device.