Modeling charge relaxation in graphene quantum dots induced by electron-phonon interaction

TL;DR

This paper compares two theoretical models of charge relaxation in graphene quantum dots caused by electron-phonon interactions, predicting relaxation times that inform experimental observations and highlight the impact of confinement methods.

Contribution

It introduces and compares two analytic models for charge relaxation in graphene quantum dots, emphasizing the influence of confinement type on relaxation times.

Findings

Electrostatically confined quantum dots have longer relaxation times.

Relaxation times in electrostatic models exceed 100 ns, aligning with experimental bounds.

Pure edge confinement results in shorter relaxation times.

Abstract

We study and compare two analytic models of graphene quantum dots for calculating charge relaxation times due to electron-phonon interaction. Recently, charge relaxation processes in graphene quantum dots have been probed experimentally and here we provide a theoretical estimate of relaxations times. By comparing a model with pure edge confinement to a model with electrostatic confinement, we find that the latter features much larger relaxation times. Interestingly, relaxation times in electrostatically defined quantum dots are predicted to exceed the experimentally observed lower bound of ~100 ns.