Device Applications of Spin-Orbit Interaction in Semiconductor Heterostructures

We report recent progress in theoretical development of two classes of non-magnetic semiconductor heterostructure spin devices that exploit spin-orbit interaction in the presence of structural inversion asymmetry (SIA) or bulk inversion asymmetry (BIA). The first uses resonant tunneling to filter spins, and can be used to create a source of spin polarized current. We will provide an analysis on the origin of spin-dependent tunneling in these structures and discuss their applications. The second exploits the interplay between BIA and SIA to control spin lifetimes for device applications. We show that the D'yakonov-Perel' spin relaxation can be suppressed to first order in $k$ for one out three spin components in [001] and [011] heterostructures, and for all three spin components in [111] heterostructures. Our results suggest the use of [111] heterostructures as preferred channels for spin transport, as active regions in spin-LEDs, for spin lifetime transistor, and for spin storage.