Chaotic Dirac billiard in graphene quantum dots

TL;DR

This paper investigates transport properties of graphene quantum dots, revealing size-dependent behaviors and chaotic quantum confinement effects, with implications for molecular-scale electronics.

Contribution

It demonstrates the transition from classical to chaotic quantum behavior in graphene quantum dots and explores their potential for molecular electronics.

Findings

Large dots show Coulomb blockade peaks

Small dots exhibit non-periodic peak spacing

Confinement gap up to 0.5 eV in narrow constrictions

Abstract

We report on transport characteristics of quantum dot devices etched entirely in graphene. At large sizes, they behave as conventional single-electron transistors, exhibiting periodic Coulomb blockade peaks. For quantum dots smaller than 100 nm, the peaks become strongly non-periodic indicating a major contribution of quantum confinement. Random peak spacing and its statistics are well described by the theory of chaotic neutrino (Dirac) billiards. Short constrictions of only a few nm in width remain conductive and reveal a confinement gap of up to 0.5eV, which demonstrates the in-principle possibility of molecular-scale electronics based on graphene.