Resonant interband tunneling spin filter

We propose an InAs/GaSb/AlSb-based asymmetric resonant interband tunneling diode as a spin filter. The interband design exploits large valence band spin-orbit interaction to provide strong spin selectivity, without suffering from fast hole spin relaxation. Spin filtering efficiency is also enhanced by the reduction of tunneling through quasibound states near the zone center, where spin spitting vanishes and spin selectivity is difficult. Our calculations show that, when coupled with an emitter or collector capable of lateral momentum selectivity, the asymmetric resonant interband tunneling diode can achieve significant spin filtering in conventional nonmagnetic semiconductor heterostructures under zero magnetic field. (C) 2002 American Institute of Physics.