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arXiv · 2402.18328

Valley relaxation in a single-electron bilayer graphene quantum dot

Lin Wang·Guido Burkard
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Abstract

We investigate the valley relaxation due to intervalley coupling in a single-electron bilayer graphene quantum dot. The valley relaxation is assisted by both the emission of acoustic phonons via the deformation potential and bond-length change mechanisms and $1/f$ charge noise. In the perpendicular magnetic-field dependence of the valley relaxation time $T_1$, we predict a monotonic decrease of $T_1$ at higher fields due to electron-phonon coupling, which is in good agreement with recent experiments by Banszerus et al. We find that the dominant valley relaxation channel in the high-field regime is the electron-phonon coupling via the deformation potential. At lower fields, we predict that a peak in $T_1$ can arise from the competition between $1/f$ charge noise and electron-phonon scattering due to bond-length change. We also find that the interlayer hopping $\gamma_3$ opens a valley relaxation channel for electric charge noise for rotationally symmetric quantum dots in bilayer graphene.

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Lin Wang, Guido Burkard. 2024-02-28. Valley relaxation in a single-electron bilayer graphene quantum dot. https://arxiv.org/abs/2402.18328

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