Ambipolar spin diffusion in p-type GaAs: A case where spin diffuses more than charge
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 r...
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Veröffentlicht in: | Journal of applied physics 2017-09, Vol.122 (9) |
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Hauptverfasser: | , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | 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. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.4985831 |