Gate-defined graphene double quantum dot and excited state spectroscopy

TL;DR

This paper demonstrates the creation of a graphene double quantum dot using gate-defined nanostructures, enabling detailed spectroscopy of excited states and extraction of key electronic parameters.

Contribution

It introduces a method to form and tune a graphene double quantum dot with independent control over electron numbers and coupling, providing new insights into its excited state spectrum.

Findings

Transport through excited states observed in weakly coupled regime

Capacitances and level spacing quantitatively extracted

Double quantum dot tunability demonstrated

Abstract

A double quantum dot is formed in a graphene nanoribbon device using three top gates. These gates independently change the number of electrons on each dot and tune the inter-dot coupling. Transport through excited states is observed in the weakly coupled double dot regime. We extract from the measurements all relevant capacitances of the double dot system, as well as the quantized level spacing.