Carbon nanotubes as ultra-high quality factor mechanical resonators

TL;DR

This paper demonstrates that suspended carbon nanotubes can serve as ultra-high quality factor mechanical resonators with tunable frequencies and minimal damping, suitable for advanced nanoelectromechanical applications.

Contribution

It reports the first observation of high-Q, gate-tunable mechanical resonances in suspended carbon nanotubes at millikelvin temperatures using a contact-free actuation method.

Findings

Resonance frequencies up to 350 MHz

Quality factors exceeding 10^5

Resonators can be driven into non-linear regime

Abstract

We have observed the transversal vibration mode of suspended carbon nanotubes at millikelvin temperatures by measuring the single-electron tunneling current. The suspended nanotubes are actuated contact-free by the radio frequency electric field of a nearby antenna; the mechanical resonance is detected in the time-averaged current through the nanotube. Sharp, gate-tuneable resonances due to the bending mode of the nanotube are observed, combining resonance frequencies of up to \nu_0 = 350 MHz with quality factors above Q = 10^5, much higher than previously reported results on suspended carbon nanotube resonators. The measured magnitude and temperature dependence of the Q-factor shows a remarkable agreement with the intrinsic damping predicted for a suspended carbon nanotube. By adjusting the RF power on the antenna, we find that the nanotube resonator can easily be driven into the non-linear regime.