Spin accumulation near Fe/GaAs (001) interfaces: The role of semiconductor band structure
Spin accumulation near Fe/GaAs (001) interfaces: The role of semiconductor band structure
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DOI：
10.1103/physrevb.84.085306
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发表时间：
2011-08
影响因子：
3.7
通讯作者：
Q. Hu;E. Garlid;P. Crowell;C. Palmstrøm
中科院分区：
文献类型：
--
作者：
Q. Hu;E. Garlid;P. Crowell;C. Palmstrøm
我们证明肖特基隧道势垒异质结构中 Fe/GaAs (001) 界面附近形成的简并区在自旋输运中起着重要作用。首先，它是在没有施加偏置电压的情况下存在显着自旋电流的先决条件，这对于电自旋检测至关重要。其次，它建立了一个明确的电化学势库，充当流入半导体主体的自旋电流源。速率方程分析表明，对于5×10 18 cm - 3 的Si掺杂，界面处高掺杂GaAs层的最佳厚度在20至25 nm范围内，与实验结果相当吻合。正如退火实验所证明的那样，自旋电流的符号和大小都对界面电子结构中非常小的变化敏感。
We show that the degenerate region which forms in the vicinity of the Fe/GaAs (001) interface in Schottky tunnel barrier heterostructures plays an important role in spin transport. First, it is a prerequisite for a significant spin current to exist in the absence of an applied bias voltage, which is essential for electrical spin detection. Second, it establishes a well-defined electrochemical potential reservoir which functions as the source of spin currents flowing into the bulk of the semiconductor. A rate equation analysis shows that the optimal thickness of the highly doped GaAs layer at the interface is in the range of 20 to 25 nm for Si dopings of 5 × 10 18 cm − 3 , in reasonable agreement with experiment. Both the sign and magnitude of the spin currents are sensitive to very small changes in interfacial electronic structure, as demonstrated in annealing experiments.