Ambipolar spin diffusion in p-type GaAs: A case where spin diffuses more than charge

作者：Cadiz F^*; Notot V; Filipovic J; Paget D; Weber C P; Martinelli L; Rowe A C H; Arscott S

来源：Journal of Applied Physics, 2017, 122(9): 095703.

DOI：10.1063/1.4985831

We investigate the diffusion of charge and spin at 15K in p-type GaAs, combining transient-grating and energy-resolved microluminescence measurements to cover a broad range of photoelectron density. At very low optical power, in a unipolar nondegenerate regime, charge and spin diffuse at the same rate, implying that the spin-drag effects are negligible. Upon increasing the photoelectron concentration up to about 10(16) cm(-3), the charge diffusion constant decreases because of ambipolar electrostatic interactions with the slower-diffusing holes while the spin diffusion constant is reduced only weakly by the ambipolar interaction. A further increase in the excitation power causes increases in both the charge and spin diffusion constants as a consequence of the Pauli principle since the photoelectron gas becomes degenerate. Published by AIP Publishing.

• 出版日期2017-9-7