Gate-Defined Quantum Dots on Carbon Nanotubes

TL;DR

This paper demonstrates the creation and control of quantum dots in carbon nanotubes using local electrostatic gates, enabling precise manipulation of quantum states for potential nanoelectronic and quantum computing applications.

Contribution

It introduces a method to define and control multiple quantum dots on a single nanotube via electrostatic gating, advancing nanotube-based quantum device design.

Findings

Quantum dots can be precisely defined using local electrostatic gates.

Tunnel barrier transparencies and electrostatic energies are tunable with gate voltages.

Multiple quantum dots can be controlled on a single nanotube.

Abstract

We report the realization of nanotube-based quantum dot structures that use local electrostatic gating to produce individually controllable dots in series along a nanotube. Electrostatic top-gates produce depletion regions in the underlying tube; a pair of such depletion regions defines a quantum dot. Transparencies of tunnel barriers as well as the electrostatic energies, within single and multiple dots, can be tuned by gate voltages. The approach allows accurate control over multiple devices on a single tube, and serves as a design paradigm for nanotube-based electronics and quantum systems.