Stich, Dominik and Zhou, J. and Korn, Tobias and Schulz, Robert and Schuh, Dieter and Wegscheider, Werner and Wu, Meng W. and Schüller, Christian
Effect of Initial Spin Polarization on Spin Dephasing and the Electron g Factor in a High-Mobility Two-Dimensional Electron System.
Physical Review Letters 98 (17), p. 175041.
We have investigated the spin dynamics of a high-mobility two-dimensional electron system (2DES) in a GaAs-Al0.3Ga0.7As single quantum well by time-resolved Faraday rotation in dependence on the initial degree of spin polarization, P, of the 2DES. From P∼0 to P∼30%, we observe an increase of the spin dephasing time, T2*, by an order of magnitude, from about 20 ps to 200 ps, in good agreement with theoretical predictions by Weng and Wu [Phys. Rev. B 68, 075312 (2003)]. Furthermore, also the electron g factor is found to decrease for increasing P. Fully microscopic calculations reproduce the most salient features of the experiments, i.e., a dramatic decrease of spin dephasing and a moderate decrease of the electron g factor with increasing P. We show that both results are determined dominantly by the Hartree-Fock contribution of the Coulomb interaction.