Observation of excited states in a graphene double quantum dot

TL;DR

This paper investigates excited states in a graphene double quantum dot across various coupling regimes, revealing electronic excited states and tunnel barrier effects through experimental observations.

Contribution

It provides the first detailed experimental analysis of excited states in a graphene double quantum dot, highlighting the effects of different coupling regimes.

Findings

Detection of electronic excited states within the quantum dot system

Identification of tunnel barrier modulations affecting transport

Observation of structures inside finite-bias triangles

Abstract

We study a graphene double quantum dot in different coupling regimes. Despite the strong capacitive coupling between the dots, the tunnel coupling is below the experimental resolution. We observe additional structures inside the finite-bias triangles, part of which can be attributed to electronic excited dot states, while others are probably due to modulations of the transmission of the tunnel barriers connecting the system to source and drain leads.