Quasi-bound states of quantum dots in single and bilayer graphene

TL;DR

This paper investigates quasi-bound states of Dirac fermions in quantum dots within single and bilayer graphene, revealing how their lifetimes and energy levels depend on orbital momentum and energy relative to the barrier height.

Contribution

It introduces a detailed analysis of quasi-bound states in graphene quantum dots, highlighting the dependence on orbital momentum and energy, and predicts a significant decrease in energy broadening near the barrier height.

Findings

Broadening decreases with orbital momentum in graphene

Broadening increases with orbital momentum in bilayer graphene

Energy levels near the barrier height show reduced broadening due to total internal reflection

Abstract

Dirac fermions interacting with a cylindrically symmetric quantum dot potential created in single and bilayer graphene are not confined but form quasi-bound states. The broadening of these quasi-bound states (i. e. the inverse of their lifetimes) decreases (increases) with the orbital momentum of the electron in the case of graphene (bilayer). Quasi-bound states with energy below (above) the barrier height are dominantly electron(hole)-like. A remarkable decrease of the energy level broadening is predicted for electron energies close to the barrier height, which are a consequence of the total internal reflection of the electronic wave at the dot edge.