Tuning of energy levels and optical properties of graphene quantum dots

TL;DR

This paper theoretically studies the magnetic and optical properties of hexagonal graphene quantum dots, revealing edge states, Hofstadter-butterfly spectra, and tunable optical features influenced by size, edge type, and magnetic field.

Contribution

It introduces a detailed theoretical analysis of magnetic levels and optical properties of GQDs, highlighting the effects of edge type and magnetic field on their electronic behavior.

Findings

Discovery of a zero-energy edge state in zigzag GQDs

Magnetic levels form Hofstadter-butterfly spectrum

Optical properties are tunable by size, edge, and magnetic field

Abstract

We investigate theoretically the magnetic levels and optical properties of zigzag- and armchair-edged hexagonal graphene quantum dots (GQDs) utilizing the tight-binding method. A new bound edge state at zero energy appears for the zigzag GQDs in the absence of a magnetic field. The magnetic levels of GQDs exhibit a Hofstadter-butterfly spectrum and approach the Landau levels of two-dimensional graphene as the magnetic field increases. The optical properties are tuned by the size, the type of the edge, and the external magnetic field.