Hyperfine-phonon spin relaxation in a single-electron GaAs quantum dot.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30150721.
- Also identified by DOI 10.1038/s41467-018-05879-x and PMC identifier 6110844.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Understanding and control of the spin relaxation time T<sub>1</sub> is among the key challenges for spin-based qubits. A larger T<sub>1</sub> is generally favored, setting the fundamental upper limit to the qubit coherence and spin readout fidelity. In GaAs quantum dots at low temperatures and high in-plane magnetic fields B, the spin relaxation relies on phonon emission and spin-orbit coupling. The characteristic dependence T<sub>1</sub> ∝ B<sup>-5</sup> and pronounced B-field anisotropy were already confirmed experimentally. However, it has also been predicted 15 years ago that at low enough fields, the spin-orbit interaction is replaced by the coupling to the nuclear spins, where the relaxation becomes isotropic, and the scaling changes to T<sub>1</sub> ∝ B<sup>-3</sup>. Here, we establish these predictions experimentally, by measuring T<sub>1</sub> over an unprecedented range of magnetic fields-made possible by lower temperature-and report a maximum T<sub>1</sub> = 57 ± 15 s at the lowest fields, setting a record electron spin lifetime in a nanostructure.