We investigated the spin-orbit (SO) effective magnetic-field-induced spin precession of a high-mobility two-dimensional electron gas (2DEG) in a modulation-doped (001) GaAs/AlGaAs quantum well close to the persistent spin helix (PSH) state. The oscillating spin signal induced by the SO fields in zero external magnetic fields was clearly observed. When the photoexcited carrier density is sufficiently small compared with the 2DEG density, the spin precession length in the space domain was obtained by analyzing the precession frequency in the PSH regime. The excitation density dependence of the spin dynamics was reproduced well using the scattering time-dependent spin dynamics simulation. We revealed that the increase in the photoexcited carriers results in a transition from ballistic motion to diffusive motion, leading to a decrease in the spin-diffusion coefficient.

中文翻译：

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持续自旋螺旋态下高迁移率二维电子气的零场自旋进动动力学

我们研究了自旋轨道（SO）在高掺杂二维（001）GaAs / AlGaAs量子阱中的高迁移率二维电子气（2DEG）的自旋进动，该量子阱与持久自旋螺旋（ PSH）状态。清楚地观察到在零外部磁场中由SO场感应的振荡自旋信号。当光激发载流子密度与2DEG密度相比足够小时，通过分析PSH体制中的进动频率，获得了空间域中的自旋进动长度。使用散射时间相关的自旋动力学模拟很好地再现了自旋动力学的激发密度依赖性。我们发现光激发载流子的增加导致了从弹道运动到扩散运动的转变，