Weak localization and weak antilocalization in doped germanium epilayers
Applied Physics Letters
American Institute of Physics
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Newton, P., Mansell, R., Holmes, S., Myronov, M., & Barnes, C. (2017). Weak localization and weak antilocalization in doped germanium epilayers. Applied Physics Letters, 110 (6. 062101)https://doi.org/10.1063/1.4975600
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 lφ∝Tc, 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.
Is supplemented by: https://doi.org/10.17863/CAM.7415
This work was supported by the EPSRC funded “Spintronic device physics in Si/Ge heterostructures” EP/J003263/1 and EP/J003638/1 projects and a Platform Grant No. EP/J001074/1.
External DOI: https://doi.org/10.1063/1.4975600
This record's URL: https://www.repository.cam.ac.uk/handle/1810/262623