Phonon-induced electron relaxation in quantum rings

We study electron-acoustic phonon scattering and electron relaxation in quantum rings in the absence and in the presence of external magnetic fields. Electron-phonon interaction is accounted for both the deformation potential and piezoelectric coupling. At zero magnetic field and small ring radius, the deformation potential phonon scattering is orders of magnitude larger than the piezoelectric one. However, the piezoelectric coupling is found to become important when the ring radius and magnetic field increase. It can be the dominant scattering mechanism at large ring radii and/or large magnetic fields. In comparison with the quantum dot case, the acoustic phonon scattering is stronger in quantum rings.