Defining and controlling double quantum dots in single-walled carbon nanotubes

TL;DR

This paper demonstrates the experimental creation and control of double quantum dots in single-walled carbon nanotubes using top-gate electrodes, enabling local gating and tuning of quantum states.

Contribution

It presents a novel device architecture with top-gates that can define and manipulate double quantum dots in nanotubes, advancing quantum dot control techniques.

Findings

Double quantum dots observed via honeycomb charge stability patterns

Top-gates enable local gating and chemical potential tuning

Device operates consistently across multiple samples

Abstract

We report the experimental realization of double quantum dots in single-walled carbon nanotubes. The device consists of a nanotube with source and drain contact, and three additional top-gate electrodes in between. We show that, by energizing these top-gates, it is possible to locally gate a nanotube, to create a barrier, or to tune the chemical potential of a part of the nanotube. At low temperatures we find (for three different devices) that in certain ranges of top-gate voltages our device acts as a double quantum dot, evidenced by the typical honeycomb charge stability pattern.