Spin concentration grating and electron spin ambipolar diffusion in intrinsic GaAs multiple quantum wells
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摘要: 为研究空穴对自旋极化电子扩散的影响,提出用自旋密度光栅方法来观察电子自旋扩散过程。由飞秒激光在本征GaAs多量子阱中激发产生瞬态自旋光栅和瞬态自旋密度光栅,并用于研究电子自旋扩散和电子自旋双极扩散。实验测得自旋双极扩散系数Das=25.4 cm2/s,低于自旋扩散系数Ds=113.0 cm2/s,表明自旋密度光栅中电子自旋扩散受到空穴的显著影响。Abstract: In order to research the effect of holes on the spin electron diffusion, a method of resonant spin amplication called Spin Concentration Grating(SCG) is adopt to observe the process of electron spin diffusion. Transient spin grating and spin concentration grating excited by femtosecond laser beams are used to investigate electron spin diffusion and electron spin ambipolar diffusion in intrinsic GaAs multiple quantum wells. The measured coefficient of electron spin ambipolar diffusion Das=25.4 cm2s-1 is lower than that of electron spin diffusion Ds=113.0 cm2s-1, which indicates that the influence of holes on electron spin diffusion in spin concentration grating is notable.
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