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arXiv · 0902.0270

Ultrafast Spin Dynamics in Optically Excited Bulk GaAs at Low Temperatures

M. Krauss·R. Bratschitsch·Z. Chen·S. T. Cundiff·H. C. Schneider
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Abstract

This paper presents a study of electron spin dynamics in bulk GaAs at low temperatures for elevated optical excitation conditions. Our time-resolved Faraday rotation measurements yield sub-nanosecond electron spin dephasing-times over a wide range of n-doping concentrations in quantitative agreement with a microscopic treatment of electron spin dynamics. The calculation shows the occurrence and breakdown of motional narrowing for spin dephasing under elevated excitation conditions. We also find a peak of the spin dephasing time around a doping density for which, under lower excitation conditions, a metal-insulator transition occurs. However, the experimental results for high excitation can be explained without a metal-insulator transition. We therefore attribute the peak in spin-dephasing times to the influence of screening and scattering on the spin-dynamics of the excited electrons.

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M. Krauss, R. Bratschitsch, Z. Chen, S. T. Cundiff, H. C. Schneider. 2009-10-18. Ultrafast Spin Dynamics in Optically Excited Bulk GaAs at Low Temperatures. https://doi.org/10.1103/physrevb.81.035213

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