Graphene quantum dots formed by a spatial modulation of the Dirac gap

TL;DR

This paper demonstrates that a spatial modulation of the Dirac gap in graphene can create quantum dot states with discrete energy levels without external electric or magnetic fields, enabling tunable confinement.

Contribution

It introduces a novel method to form quantum dots in graphene via Dirac gap modulation, bypassing Klein tunnelling limitations.

Findings

Gap modulation induces confined states in graphene.

These states coexist and couple with electrostatic potential states.

The localization region can be tuned with electrostatic potential.

Abstract

An electrostatic quantum dot cannot be formed in monolayer graphene, because of the Klein tunnelling. However, a dot can be formed with the help of a uniform magnetic field. As shown here, a spatial modulation of the Dirac gap leads to confined states with discrete energy levels, thus defining a dot, without applying external electric and magnetic fields. Gap-induced dot states can coexist and couple with states introduced by an electrostatic potential. This property allows the region in which the resulting states are localized to be tuned with the potential.