Landau level mixing by full spin-orbit interactions

The manipulation of the spin of charge carriers in semiconductors, spintronics, has attracted increasing interest in recent years. In the paradigmatic Datta-Das spin transistor, 1 the spin of the electron passing through the device is controlled by the Rashba spin-orbit (SO) interaction, 2 which in turn can be varied by the application of gate voltages. The Rashba interaction stems from the structural inversion asymmetry (SIA) introduced by a heterojunction or by surface or external fields. In semiconductors with narrower energy gap (InGaAs, AlGaAs), this effect is expected to be stronger. It has been shown experimentally that the Rashba spin-orbit interaction can be modified up to 50% by external gate voltages. 3,4 In addition to the Rashba coupling there is also a material-intrinsic Dresselhaus spin-orbit interaction. This originates from the bulk inversion asymmetry (BIA) of the crystal, and can be relatively large in semiconductors like InSb/InAlSb. 5