Phonon-assisted relaxation between triplet and singlet states in a self-assembled double quantum dot

• Main Authors: Krzysztof Gawarecki, Paweł Machnikowski
• Format: Article
• Language: English
• Published: Nature Publishing Group 2021-07-01
• Series: Scientific Reports
• Online Access: https://doi.org/10.1038/s41598-021-94621-7

Abstract We study theoretically phonon-induced spin dynamics of two electrons confined in a self-assembled double quantum dot. We calculate the transition rates and time evolution of occupations for the spin-triplet and spin-singlet states. We characterize the relative importance of various relaxation channels, including two-phonon processes, as a function of the electric and magnetic fields. The simulations are based on a model combining the eight-band $$\varvec{k}\!\cdot \!\varvec{p}$$ k · p method and configuration-interaction approach. We show that the electron g-factor mismatch between the Zeeman doublets localized on different dots opens a relatively fast triplet-singlet phonon-assisted relaxation channel. We also demonstrate, that the relaxation near the triplet-singlet anticrossing is slowed down up to several orders of magnitude due to vanishing of some relaxation channels.