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arXiv · 0903.0783

Phonon-induced dephasing of singlet-triplet superpositions in double quantum dots without spin-orbit coupling

Katarzyna Roszak·Pawel Machnikowski
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Abstract

We show that singlet-triplet superpositions of two-electron spin states in a double quantum dot undergo a phonon-induced pure dephasing which relies only on the tunnel coupling between the dots and on the Pauli exclusion principle. As such, this dephasing process is independent of spin-orbit coupling or hyperfine interactions. The physical mechanism behind the dephasing is elastic phonon scattering, which persists to much lower temperatures than real phonon-induced transitions. Quantitative calculations performed for a lateral GaAs/AlGaAs gate-defined double quantum dot yield micro-second dephasing times at sub-Kelvin temperatures, which is consistent with experimental observations.

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Katarzyna Roszak, Pawel Machnikowski. 2010-09-14. Phonon-induced dephasing of singlet-triplet superpositions in double quantum dots without spin-orbit coupling. https://doi.org/10.1103/physrevb.80.195315

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