Electron Scattering in Gapped Graphene Quantum Dots

TL;DR

This paper investigates how an induced energy gap in graphene quantum dots affects electron scattering, revealing three distinct regimes and analyzing how system parameters influence scattering resonances.

Contribution

It introduces the effect of an energy gap on scattering regimes in graphene quantum dots, expanding understanding beyond the gapless case.

Findings

Identification of three scattering regimes due to the energy gap

Analysis of scattering efficiency dependence on energy, radius, and gap

Discussion of parameter effects on scattering resonances

Abstract

Due to Klein tunneling in graphene only quasi-bound states are realized in graphene quantum dots by electrostatic gating. Particles in the quasi-bound states are trapped inside the dot for a finite time and they keep bouncing back and forth till they find their way out. Here we study the effect of an induced gap on the scattering problem of Dirac electrons on a circular electrostatically confined quantum dot. Introducing an energy gap inside the quantum dot enables us to distinguish three scattering regimes instead of two in the case of gapless graphene quantum dot. We will focus on these regimes and analyze the scattering efficiency as a function of the electron energy, the dot radius and the energy gap. Moreover, we will discuss how the system parameters can affect the scattering resonances inside the dot.