Dirac gap-induced graphene quantum dot in an electrostatic potential

TL;DR

This paper investigates how a spatially varying Dirac gap in graphene can create quantum dots through charge confinement, and explores the coupling of these states with electrostatic potentials, revealing tunable hybridized states.

Contribution

It provides a continuum model analysis of gap-induced quantum dots in graphene, demonstrating coupling with electrostatic potentials and potential for tunable quantum states.

Findings

Confined states are localized in regions with a local minimum of the Dirac gap.

Hybridized states can be tuned via electrostatic potential strength.

The study offers insights into quasi-relativistic effects in graphene.

Abstract

A spatially modulated Dirac gap in a graphene sheet leads to charge confinement, thus enabling a graphene quantum dot to be formed without the application of external electric and magnetic fields [Appl. Phys. Lett. \textbf{97}, 243106 (2010)]. This can be achieved provided the Dirac gap has a local minimum in which the states become localised. In this work, the physics of such a gap-induced dot is investigated in the continuum limit by solving the Dirac equation. It is shown that gap-induced confined states couple to the states introduced by an electrostatic quantum well potential. Hence the region in which the resulting hybridized states are localised can be tuned with the potential strength, an effect which involves Klein tunneling. The proposed quantum dot may be used to probe quasi-relativistic effects in graphene, while the induced confined states may be useful for graphene-based nanostructures.