Strong coupling between single-electron tunneling and nano-mechanical motion

TL;DR

This paper demonstrates strong coupling between single-electron tunneling and nano-mechanical motion in a carbon nanotube resonator, revealing charge-induced frequency shifts, energy transfer effects, and self-driven mechanical oscillations.

Contribution

It provides experimental evidence of strong electromechanical coupling at the single-electron level in a high-Q nanotube resonator, including charge-induced frequency shifts and self-excitation phenomena.

Findings

Single-electron charge causes measurable shifts in resonance frequency.

Energy transfer from electrons leads to mechanical damping and nonlinear effects.

A direct current can spontaneously drive the mechanical resonator.

Abstract

Nanoscale resonators that oscillate at high frequencies are useful in many measurement applications. We studied a high-quality mechanical resonator made from a suspended carbon nanotube driven into motion by applying a periodic radio frequency potential using a nearby antenna. Single-electron charge fluctuations created periodic modulations of the mechanical resonance frequency. A quality factor exceeding 10^5 allows the detection of a shift in resonance frequency caused by the addition of a single-electron charge on the nanotube. Additional evidence for the strong coupling of mechanical motion and electron tunneling is provided by an energy transfer to the electrons causing mechanical damping and unusual nonlinear behavior. We also discovered that a direct current through the nanotube spontaneously drives the mechanical resonator, exerting a force that is coherent with the high-frequency resonant mechanical motion.