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arXiv · 2307.02323

Enhanced Electron Spin Coherence in a GaAs Quantum Emitter

Giang N. Nguyen·Clemens Spinnler·Mark R. Hogg·Liang Zhai·Alisa Javadi·Carolin A. Schrader·Marcel Erbe·Marcus Wyss·Julian Ritzmann·Hans-Georg Babin·Andreas D. Wieck·Arne Ludwig·Richard J. Warburton
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Abstract

A spin-photon interface should operate with both coherent photons and a coherent spin to enable cluster-state generation and entanglement distribution. In high-quality devices, self-assembled GaAs quantum dots are near-perfect emitters of on-demand coherent photons. However, the spin rapidly decoheres via the magnetic noise arising from the host nuclei. Here, we address this drawback by implementing an all-optical nuclear-spin cooling scheme on a GaAs quantum dot. The electron-spin coherence time increases 156-fold from $T_2^*$ = 3.9 ns to 0.608 $\mu$s. The cooling scheme depends on a non-collinear term in the hyperfine interaction. The results show that such a term is present even though the strain is low and no external stress is applied. Our work highlights the potential of optically-active GaAs quantum dots as fast, highly coherent spin-photon interfaces.

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Giang N. Nguyen, Clemens Spinnler, Mark R. Hogg, Liang Zhai, Alisa Javadi, Carolin A. Schrader, Marcel Erbe, Marcus Wyss, Julian Ritzmann, Hans-Georg Babin, Andreas D. Wieck, Arne Ludwig, Richard J. Warburton. 2023-07-05. Enhanced Electron Spin Coherence in a GaAs Quantum Emitter. https://doi.org/10.1103/physrevlett.131.210805

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