Electron and spin dynamics in a single quantum emitter

TL;DR

This study explores how magnetic fields affect electron and spin dynamics in a single quantum dot, revealing key insights for quantum technologies.

Contribution

The paper introduces a method using two-color, time-resolved resonance fluorescence to measure multiple microscopic rates in a single quantum dot.

Findings

The Auger–Meitner recombination rate is suppressed for magnetic fields above 4T.

The electron spin-flip relaxation rate increases strongly for fields above 3T.

The spin-flip Raman scattering rate remains nearly constant across the magnetic field range.

Abstract

The Auger–Meitner effect is a fundamental electron–electron scattering process that impacts the electron and spin dynamics in semiconductor quantum emitters, such as colloidal nanocrystals and quantum dots. Here, we present an experimental study of the magnetic-field dependence of Auger–Meitner recombination and spin-related scattering processes in a single self-assembled InAs quantum dot. Using two-color, time-resolved resonance fluorescence with spectrally separated detection of both exciton and trion transitions, we extract the Auger–Meitner recombination rate, the electron spin-flip relaxation rate, and the spin-flip Raman scattering rate over a broad magnetic-field range from \documentclass[12pt]{minimal}
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\begin{document}$$B = 0$$\end{document}B=0 to \documentclass[12pt]{minimal}
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\begin{document}$$8\,\textrm{T}$$\end{document}8T. We observe a suppression of the Auger–Meitner recombination rate for magnetic fields above \documentclass[12pt]{minimal}
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\begin{document}$$B = 4\,\textrm{T}$$\end{document}B=4T. In contrast, the electron spin-flip relaxation rate increases strongly for fields above \documentclass[12pt]{minimal}
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\begin{document}$$B = 3\,\textrm{T}$$\end{document}B=3T and decreases at lower magnetic fields, while the spin-flip Raman scattering rate remains nearly constant. Our results demonstrate that two-color, time-resolved resonance fluorescence enables access to all relevant microscopic rates for optimizing quantum dots as building blocks for future quantum technologies.

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