Electron confinement in graphene with gate-defined quantum dots

TL;DR

This paper investigates how to electrostatically confine electrons in graphene nanoribbons using gate-defined quantum dots, revealing quantum resonances and tunable conductance in such nanostructures.

Contribution

The study provides a theoretical analysis of electron confinement in graphene quantum dots, highlighting quantum effects and tunable transport properties via gate voltages.

Findings

Quantum resonances dominate scattering cross-sections for small dots.

Resonant scattering leads to quasi-bound states in quantum dots.

Conductance can be tuned by adjusting gate voltages.

Abstract

We theoretically analyse the possibility to electrostatically confine electrons in circular quantum dot arrays, impressed on contacted graphene nanoribbons by top gates. Utilising exact numerical techniques, we compute the scattering efficiency of a single dot and demonstrate that for small-sized scatterers the cross-sections are dominated by quantum effects, where resonant scattering leads to a series of quasi-bound dot states. Calculating the conductance and the local density of states for quantum dot superlattices we show that the resonant carrier transport through such graphene-based nanostructures can be easily tuned by varying the gate voltage.