American Institute of Physics Publishing
We investigate the diffusion of charge and spin at 15 K 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 1016 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.
Cadiz, F., Notot, V., Filipovic, J., Paget, D., Weber, C. P., Martinelli, L., … Arscott, S. (2017). Ambipolar spin diffusion in p-type GaAs: A case where spin diffuses more than charge. Journal of Applied Physics, 122(9), 095703. https://doi.org/10.1063/1.4985831