Weak localization and weak antilocalization in doped germanium epilayers
Weak localization and weak antilocalization in doped germanium epilayers
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DOI：
10.1063/1.4975600
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发表时间：
2017-02-06
影响因子：
4
通讯作者：
Barnes, C. H. W.
中科院分区：
文献类型：
--
作者：
Newton, P. J.;Mansell, R.;Barnes, C. H. W.
在低至 1.6 K 的温度范围内测量了 50 nm 厚的掺杂锗外延层的磁阻。n 型和 p 型器件都显示出对所施加磁场中的电导率的量子校正，其中 n 型器件显示出弱局域化，p 型器件显示出弱反局域化。使用 Hikami-Larkin-Nagaoka 模型对这些数据进行拟合，提取每个器件的相位相干长度以及 p 型器件的自旋扩散长度。我们在高掺杂 n 型器件中获得了高达 325 nm 的相位相干长度，这为量子技术中的应用提供了可能。尽管传导性质存在明显差异，但对于每个器件，相位相干长度随温度的衰减遵循与 T-c 成比例的相同幂律 1(phi)，其中 c = -0.68 +/- 0.03。在 p 型器件中，测量的自旋扩散长度在可以观察到弱反局域化的温度范围内不会发生变化。自旋轨道相互作用的存在表现为 p 型外延层中的弱反局域化，这表明这些结构可以开发用于自旋电子器件，例如自旋 FET，其中显着的自旋寿命对于器件的高效运行非常重要。由 AIP 出版社出版。
The magnetoresistance of 50 nm thick epilayers of doped germanium is measured at a range of temperatures down to 1.6 K. Both n- and p-type devices show quantum corrections to the conductivity in an applied magnetic field, with n-type devices displaying weak localization and p-type devices showing weak antilocalization. From fits to these data using the Hikami-Larkin-Nagaoka model, the phase coherence length of each device is extracted, as well as the spin diffusion length of the p-type device. We obtain phase coherence lengths as large as 325 nm in the highly doped n-type device, presenting possible applications in quantum technologies. The decay of the phase coherence length with temperature is found to obey the same power law of 1(phi) proportional to T-c, where c = -0.68 +/- 0.03, for each device, in spite of the clear differences in the nature of the conduction. In the p-type device, the measured spin diffusion length does not change over the range of temperatures for which weak antilocalization can be observed. The presence of a spin-orbit interaction manifested as weak antilocalization in the p-type epilayer suggests that these structures could be developed for use in spintronic devices such as the spin-FET, where significant spin lifetimes would be important for efficient device operation. Published by AIP Publishing.