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arXiv · 0708.2792

Long nuclear spin decay times controlled by optical pumping in individual quantum dots

M. N. Makhonin·A. I. Tartakovskii·I. Drouzas·A. B. Van'kov·T. Wright·J. Skiba-Szymanska·A. Russell·V. I. Fal'ko·M. S. Skolnick·H. -Y. Liu·M. Hopkinson
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Abstract

Nuclear polarization dynamics are measured in the nuclear spin bi-stability regime in a single optically pumped InGaAs/GaAs quantum dot. The controlling role of nuclear spin diffusion from the dot into the surrounding material is revealed in pump-probe measurements of the non-linear nuclear spin dynamics. We measure nuclear spin decay times in the range 0.2-5 sec, strongly dependent on the optical pumping time. The long nuclear spin decay arises from polarization of the material surrounding the dot by spin diffusion for long (>5sec) pumping times. The time-resolved methods allow the detection of the unstable nuclear polarization state in the bi-stability regime otherwise undetectable in cw experiments.

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M. N. Makhonin, A. I. Tartakovskii, I. Drouzas, A. B. Van'kov, T. Wright, J. Skiba-Szymanska, A. Russell, V. I. Fal'ko, M. S. Skolnick, H. -Y. Liu, M. Hopkinson. 2007-08-21. Long nuclear spin decay times controlled by optical pumping in individual quantum dots. https://doi.org/10.1103/physrevb.77.125307

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