Mode coupling bi-stability and spectral broadening in buckled carbon nanotube mechanical resonators

Computing, memories, and digital electronics are based on the operation principle of bi-stable systems. Here, Yaish et al. report the unusual non-linear behaviour of buckled up carbon nanotubes mechanical resonators, which allows high electrical frequency tunability and snap-through bi-stability. Bi-stable mechanical resonators play a significant role in various applications, such as sensors, memory elements, quantum computing and mechanical parametric amplification. While carbon nanotube based resonators have been widely investigated as promising NEMS devices, a bi-stable carbon nanotube resonator has never been demonstrated. Here, we report a class of carbon nanotube resonators in which the nanotube is buckled upward. We show that a small upward buckling yields record electrical frequency tunability, whereas larger buckling can achieve Euler-Bernoulli bi-stability, the smallest mechanical resonator with two stable configurations to date. We believe that these recently-discovered carbon nanotube devices will open new avenues for realizing nano-sensors, mechanical memory elements and mechanical parametric amplifiers. Furthermore, we present a three-dimensional theoretical analysis revealing significant nonlinear coupling between the in-plane and out-of-plane static and dynamic modes of motion, and a unique three-dimensional Euler-Bernoulli snap-through transition. We utilize this coupling to provide a conclusive explanation for the low quality factor in carbon nanotube resonators at room temperature, key in understanding dissipation mechanisms at the nano scale.

Automated summary

This article reports on the nonlinear behavior of carbon nanotube mechanical resonators, which enables high frequency tunability and snap-through bi-stability. The findings have implications for various applications including sensors, memory elements, and mechanical parametric amplification.