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

M. Furis·D. L. Smith·J. L. Reno·S. A. Crooker
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Abstract

In bulk n-GaAs epilayers doped near the metal-insulator transition, we study the evolution of electron spin lifetime $τ_s$ as a function of applied lateral electrical bias $E_x$. $τ_s$ is measured via the Hanle effect using magneto-optical Kerr rotation. At low temperatures (T<10 K, where electrons are partially localized and $τ_s > 100$ ns at zero bias), a marked collapse of $τ_s$ 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 $τ_s$, and strongly influences electron spin transport in this regime.

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M. Furis, D. L. Smith, J. L. Reno, S. A. Crooker. 2006-05-30. Bias-dependent electron spin lifetimes in n-GaAs and the role of donor impact ionization. https://doi.org/10.1063/1.2345608

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