Phonon-induced electron relaxation in quantum rings

TL;DR

This paper investigates how electron relaxation in quantum rings is influenced by phonon interactions, magnetic fields, and ring size, revealing that deformation potential dominates at small sizes, while piezoelectric effects become significant at larger scales and fields.

Contribution

It provides a detailed analysis of phonon-induced electron relaxation mechanisms in quantum rings, highlighting the conditions under which different phonon couplings dominate.

Findings

Deformation potential phonon scattering is much larger than piezoelectric at small ring radii.

Piezoelectric coupling becomes significant at larger radii and magnetic fields.

Electron-phonon scattering is stronger in quantum rings than in quantum dots.

Abstract

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.