Optical detection of zero-field spin precession of high mobility two-dimensional electron gas in a gated GaAs/AlGaAs quantum well

We investigated the effective magnetic field induced by spin–orbit interaction in a gated modulation-doped GaAs/AlGaAs quantum well (QW) structure. We measured the precession of the optically injected electron spins at zero magnetic field by a time-resolved Kerr rotation (TRKR) technique as a function of the gate voltage Vg. The Vg-dependence of the effective magnetic field extracted from the TRKR data was quantitatively analyzed by considering both Rashba and Dresselhaus spin–orbit interaction in a Monte Carlo simulation. With the Dresselhaus spin–orbit coupling parameter γ and the scattering time as fitting parameters, we reproduced the experimental TRKR data, from which we estimated γ∼13 eV Å3.