2024/02/28 by Wang, Lin, Burkard, Guido · 1 citation
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2402.18328
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 T1, we predict a monotonic decrease of T1 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 T1 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 γ3 opens a valley relaxation channel for electric charge noise for rotationally symmetric quantum dots in bilayer graphene.