Electron density dependence of in-plane spin relaxation anisotropy in GaAs/AlGaAs two-dimensional electron gas

The authors investigated the spin dynamics of two-dimensional electrons in (001) GaAs∕AlGaAs heterostructure using the time-resolved Kerr rotation technique under a transverse magnetic field. The in-plane spin lifetime is found to be anisotropic below 150K due to the interference of Rashba [J. Phys. C 17, 6039 (1984)] and Dresselhaus [Phys. Rev. 100, 580 (1955)] spin-orbit coupling and D’yakonov-Perel [Sov. Phys. Solid State 13, 3023 (1972)] spin relaxation. The ratio of in-plane spin lifetimes is measured directly as a function of temperature and pump power, showing that the electron density in two-dimensional electron gas channel strongly affects the Rashba spin-orbit coupling.