Bias-dependent electron spin lifetimes in n-GaAs and the role of donor impact ionization

Abstract

In bulk n-GaAs epilayers doped near the metal-insulator transition, we study the evolution of electron spin lifetime ${\tau }_s$ as a function of applied lateral electrical bias $E_x$. ${\tau }_s$ is measured via the Hanle effect using magneto-optical Kerr rotation. At low temperatures (T<10 K, where electrons are partially localized and ${\tau }_s>100$ ns at zero bias), a marked collapse of ${\tau }_s$ is observed when $E_x$ exceeds the donor impact ionization threshold at $\sim$10 V/cm. A steep increase in the concentration of warm delocalized electrons -- subject to Dyakonov-Perel spin relaxation -- accounts for the rapid collapse of ${\tau }_s$, and strongly influences electron spin transport in this regime.

arXiv comment4 pages, 3 figures

References in corpus (7)

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• Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface
• Imaging spin flows in semiconductors subject to electric, magnetic, and strain fields
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• Spin injection and detection up to room temperature in Heusler~alloy/$n$-GaAs spin valves
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• Ultrafast Spin Dynamics in Optically Excited Bulk GaAs at Low Temperatures
• Optical and electrical spin injection and spin transport in hybrid Fe/GaAs devices
• Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance
• All-electrical measurements of direct spin Hall effect in GaAs with Esaki diode electrodes
• Electron charge and spin delocalization revealed in the optically probed longitudinal and transverse spin dynamics in $n$-GaAs
• Relaxation of Electron Spin during High-Field Transport in GaAs Bulk
• Effect of electric current on optical orientation of electrons in AlGaAs/GaAs heterostructure
• Bias current dependence of the spin lifetime in insulating Al${}_{0.3}$Ga${}_{0.7}$As
• Nonuniform current density and spin accumulation in a 1 μm thick n-GaAs channel
• Time-resolved lateral spin-caloric transport of optically generated spin packets in n-GaAs