Magnetic damping of a carbon nanotube NEMS resonator

TL;DR

This paper investigates how magnetic fields induce eddy current damping in a carbon nanotube NEMS resonator, reducing self-excitation effects and increasing the resonance quality factor at cryogenic temperatures.

Contribution

It demonstrates magnetic damping as a new method to control nano-electromechanical self-excitation in carbon nanotube resonators, supported by experimental measurements and modeling.

Findings

Magnetic field suppresses self-excitation effects.

Eddy current damping increases resonance quality factor.

Resonance behavior aligns with eddy current damping model.

Abstract

A suspended, doubly clamped single wall carbon nanotube is characterized at cryogenic temperatures. We observe specific switching effects in dc-current spectroscopy of the embedded quantum dot. These have been identified previously as nano-electromechanical self-excitation of the system, where positive feedback from single electron tunneling drives mechanical motion. A magnetic field suppresses this effect, by providing an additional damping mechanism. This is modeled by eddy current damping, and confirmed by measuring the resonance quality factor of the rf-driven nano-electromechanical resonator in an increasing magnetic field.