Spin transport and spin manipulation in GaAs (110) and (111) quantum wells

Spin dephasing via the spin–orbit interaction is a major mechanism limiting the electron spin lifetime in zincblende III–V quantum wells (QWs). QWs grown along the non-conventional crystallographic directions [111] and [110] offer new interesting perspectives for the control of spin–orbit (SO) related spin dephasing mechanisms due to the special symmetries of the SO fields in these structures. In this contribution, we show that the combination of such special symmetries with the transport of carriers by the type II modulation accompanying a surface acoustic wave allows the transport of spin polarized carriers over distances of tens of μm in GaAs(110) QWs. In the case of GaAs(111), the Rashba contribution to the SO field generated by an electric field perpendicular to the QW plane is used to compensate the Dresselhaus contribution at low temperatures, leading to spin lifetimes of up to 100 ns. The compensation mechanism is less effective at high temperatures due to nonlinear terms of the Dresselhaus contribution. Perspectives to overcome this limitation via the combination of (111) structures with the transport of spins by surface acoustic waves are discussed.