Rectangular model of a ballistic spin interferometer in (001) InGaAs/InAlAs quantum wells

We report an unambiguous detection of the crytalline anisotropy of the spin-orbit interaction in (001) InAlAs/InGaAs/InAlAs quantum wells using nanofabricated rectangular loop arrays, where the sides of the constituent loops are aligned along either the [110] or [] crystallographic axis. The fabrication and measurements were performed on the epi-wafer samples whose spin properties were characterized previously [Koga et al. Phys. Rev. Lett 89 (2002) 046801]. We find that the experimentally observed spin interference patterns — the amplitude modulation of the Al’tshuler–Aronov–Spivak oscillations as a function of the gate voltage — are in good agreement with the results of the spin interferometer model extended for rectangular loops and including both the Rashba and Dresselhaus spin-orbit interactions.