Han Lifen, Zhu Yonggang, Zhang Xinhui, Tan Pingheng, Ni Haiqiao, Niu Zhichuan
State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P, O, Box 912, Beijing 100083, People's Republic of China.
Nanoscale Res Lett. 2011 Jan 12;6(1):84. doi: 10.1186/1556-276X-6-84.
Temperature and carrier density-dependent spin dynamics for GaAs/AlGaAs quantum wells (QWs) with different structural symmetries have been studied by using time-resolved Kerr rotation technique. The spin relaxation time is measured to be much longer for the symmetrically designed GaAs QW comparing with the asymmetrical one, indicating the strong influence of Rashba spin-orbit coupling on spin relaxation. D'yakonov-Perel' mechanism has been revealed to be the dominant contribution for spin relaxation in GaAs/AlGaAs QWs. The spin relaxation time exhibits non-monotonic-dependent behavior on both temperature and photo-excited carrier density, revealing the important role of non-monotonic temperature and density dependence of electron-electron Coulomb scattering. Our experimental observations demonstrate good agreement with recently developed spin relaxation theory based on microscopic kinetic spin Bloch equation approach.
利用时间分辨克尔旋转技术研究了具有不同结构对称性的GaAs/AlGaAs量子阱（QW）中温度和载流子密度依赖的自旋动力学。测量发现，与非对称设计的GaAs量子阱相比，对称设计的GaAs量子阱的自旋弛豫时间要长得多，这表明Rashba自旋轨道耦合对自旋弛豫有很强的影响。已揭示D'yakonov-Perel'机制是GaAs/AlGaAs量子阱中自旋弛豫的主要贡献。自旋弛豫时间在温度和光激发载流子密度上均表现出非单调依赖行为，揭示了电子-电子库仑散射的非单调温度和密度依赖性的重要作用。我们的实验观测结果与最近基于微观动力学自旋布洛赫方程方法发展的自旋弛豫理论吻合良好。
