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利用偏振时间分辨光谱和时间分辨Kerr旋转谱,研究了GaAs中的InAs单层和亚单层的电子自旋动力学.实验发现,在非共振激发条件下,厚度为1/3单层的InAs亚单层中电子自旋弛豫寿命长达3.4ns,而1个单层厚的InAs层的电子自旋寿命只有0.48ns;而在共振激发条件下,亚单层结构中的电子自旋寿命大大减少,只有70ps,单层InAs中电子自旋寿命没有显著变化.分析表明,低温下InAs单层和亚单层结构中,Bir-Aronov-Pikus(BAP)自旋弛豫机理占主导地位.通过改变材料结构特性和激发条件来改变电子空穴的空间相关性,从而达到控制自旋弛豫的目的.
The electron spin kinetics of both InAs monolayers and submonolayers in GaAs were investigated by polarization time-resolved spectroscopy and time-resolved Kerr rotation spectra. It was found that in the case of non-resonant excitation, InAs The electron spin relaxation lifetime of the sub-monolayer is as long as 3.4ns, while the electron spin lifetime of a single monolayer InAs layer is only 0.48ns. Under the condition of resonance excitation, the electron spin life in the sub-monolayer At 70 ps, there is no significant change in the electron spin lifetime in single InAs. The analysis shows that Bir-Aronov-Pikus (BAP) spin relaxation mechanism dominates in the InAs monolayer and sub-monolayer structure at low temperature. By changing the material structure and excitation conditions to change the spatial correlation of electron holes, so as to achieve the purpose of controlling the spin relaxation.