Density dependence of spin relaxation in GaAs quantum well at room temperatureL. H. Teng1, P. Zhang2, T. S. Lai1 and M. W. Wu2, 3
1 State Key Laboratory of Optoelectronic Materials and Technologies, Department of Physics, Zhongshan University Guangzhou, Guangdong 510275, China
2 Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China Hefei, Anhui, 230026, China
3 Department of Physics, University of Science and Technology of China - Hefei, Anhui, 230026, China
received 25 June 2008; accepted in final form 8 September 2008; published October 2008
published online 2 October 2008
Carrier density dependence of electron spin relaxation in an intrinsic GaAs quantum well is investigated at room temperature using time-resolved circularly polarized pump-probe spectroscopy. It is revealed that the spin relaxation time first increases with density in the relatively low-density regime where the linear D'yakonov-Perel' spin-orbit coupling terms are dominant, and then tends to decrease when the density is large and the cubic D'yakonov-Perel' spin-orbit coupling terms become important. These features are in good agreement with theoretical predictions on density dependence of spin relaxation by Lü et al. (Phys. Rev. B, 73 (2006) 125314). A fully microscopic calculation based on numerically solving the kinetic spin Bloch equations with both the D'yakonov-Perel' and the Bir-Aronov-Pikus mechanisms included, reproduces the density dependence of spin relaxation very well.
72.25.Rb - Spin relaxation and scattering.
78.67.De - Quantum wells.
71.10.-w - Theories and models of many-electron systems.
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