Tunable capacitive inter-dot coupling in a bilayer graphene double quantum dot

TL;DR

This paper demonstrates a tunable double quantum dot in bilayer graphene, showing control over inter-dot coupling and electronic states, which advances quantum device engineering.

Contribution

It introduces a bilayer graphene double quantum dot with tunable capacitive and tunnel couplings, enabling detailed study of electronic interactions.

Findings

Mutual capacitive inter-dot coupling of 2-6 meV.

Inter-dot tunnel coupling around 1.5 μeV.

Ability to tune quantum dot energy levels and barriers.

Abstract

We report on a double quantum dot which is formed in a width-modulated etched bilayer graphene nanoribbon. A number of lateral graphene gates enable us to tune the quantum dot energy levels and the tunneling barriers of the device over a wide energy range. Charge stability diagrams and in particular individual triple point pairs allow to study the tunable capacitive inter-dot coupling energy as well as the spectrum of the electronic excited states on a number of individual triple points. We extract a mutual capacitive inter-dot coupling in the range of 2 - 6 meV and an inter-dot tunnel coupling on the order of 1.5 {\mu}eV.