Effect of initial spin polarization on spin dephasing and electron g factor in a high-mobility two-dimensional electron system

Abstract

We have investigated the spin dynamics of a high-mobility two-dimensional electron system (2DES) in a GaAs--Al${}_{0.3}$Ga${}_{0.7}$As single quantum well by time-resolved Faraday rotation (TRFR) in dependence on the initial degree of spin polarization, $P$, of the 2DES. From $P\sim 0$ to $P\sim 30$ %, we observe an increase of the spin dephasing time, $T_2^{\ast }$, 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 {\bf 68}, 075312 (2003)]. Furthermore, by applying an external magnetic field in the Voigt configuration, also the electron $g$ factor is found to decrease for increasing $P$. Fully microscopic calculations, by numerically solving the kinetic spin Bloch equations considering the D'yakonov-Perel' and the Bir-Aronov-Pikus mechanisms, reproduce the most salient features of the experiments, {\em 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.

4 pages, 4 figures, to be published in PRL

References in corpus (2)

• High temperature spin dephasing in n-typed GaAs quantum wells
• Hot-electron effect in spin dephasing in $n$-type GaAs quantum wells

Cited by in corpus (13)

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• Density dependence of spin relaxation in GaAs quantum well at room temperature
• Spin accumulation with spin-orbit interaction
• Multi-valley spin relaxation in the presence of high in-plane electric fields in $n$-type GaAs quantum wells
• Kinetics of spin coherence of electrons in $n$-type InAs quantum wells under intense terahertz laser fields
• Hole spin relaxation in $p$-type GaAs quantum wires
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• Spin relaxation in $n$-type ZnO quantum wells
• Spin dynamics of two-dimensional electrons with Rashba spin-orbit coupling and electron-electron interactions
• Effect of Singwi-Tosi-Land-Sjölander local field correction on spin relaxation in $n$-type GaAs quantum wells at low temperature