Speaker
Gary Steele
(TU Delft)
Description
Nanoscale resonators that oscillate at high frequencies are
potentially exciting candidates for ultra-sensitive mass
detectors, as well as for probing the mechanical motion of
macroscopic objects in the quantum limit. Here, I will
discuss our recent results studying 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. A high
mechanical 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.
Single-electron charge fluctuations are found to induce
periodic modulations of the mechanical resonance
frequency. These single-electron “tuning” oscillations are a
mechanical effect that is a direct consequence of single-
electron tunneling oscillations. 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 induced by the single electron force. In the
absence of external RF driving, we discover 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.
