The current-induced spin polarization and momentum-dependent spin-orbit field were measured in ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin-polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to reproduce the experimental finding that the crystal direction with the smaller net spin-orbit field has larger electrical spin generation efficiency and are used to predict how sample parameters affect the magnitude of the current-induced spin polarization.

中文翻译：

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掺杂浓度不同的InGaAs和GaAs外延层中电流诱导的自旋极化

测量了电流诱导的自旋极化和与动量有关的自旋轨道场 ${在}_X{嘎}_{\mathrm{1个}-X}\mathrm{作为}$具有不同铟浓度和硅掺杂密度的外延层。发现具有较高铟浓度和载体浓度且迁移率较低的样品具有更高的电自旋产生效率。此外，尽管没有可测量的自旋轨道场，但仍在GaAs外延层中检测到电流诱导的自旋极化，这表明必须考虑外在因素对自旋极化机制的影响。基于模型的理论计算，除了固有的Rashba和Dresselhaus自旋轨道耦合，还包括对自旋移相和自旋霍尔效应的外在贡献，