Gate-Tunable Graphene Quantum Dot and Dirac Oscillator

TL;DR

This paper analytically solves the Dirac equation for a graphene quantum dot under a magnetic field and Dirac-oscillator potential, demonstrating tunable valley degeneracy and potential applications in quantum devices.

Contribution

It introduces an analytical solution for a graphene quantum dot with a tunable magnetic field and oscillator potential, enabling control over valley degeneracy.

Findings

Control of valley degeneracy via magnetic field tuning

Analytical energy spectrum for graphene quantum dots

Comparison with existing models and potential applications

Abstract

We obtain the solution of the Dirac equation in (2+1) dimensions in the presence of a constant magnetic field normal to the plane together with a two-dimensional Dirac-oscillator potential coupling. We study the energy spectrum of graphene quantum dot (QD) defined by electrostatic gates. We give discussions of our results based on different physical settings, whether the cyclotron frequency is similar or larger/smaller compared to the oscillator frequency. This defines an effective magnetic field that produces the effective quantized Landau levels. We study analytically such field in gate-tunable graphene QD and show that our structure allow us to control the valley degeneracy. Finally, we compare our results with already published work and also discuss the possible applications of such QD.