Entropic Spectral Broadening in Carbon Nanotube Resonators

TL;DR

This paper investigates how thermal fluctuations cause spectral broadening and frequency shifts in carbon nanotube resonators, explaining experimental observations through simulations and analytical models.

Contribution

The study introduces a mean field approach to analytically describe entropic fluctuations and their impact on spectral properties of CNT resonators.

Findings

Thermal fluctuations induce mode coupling leading to spectral broadening.

Simulations match experimental quality factors at room temperature.

Analytical calculations agree with simulation results for frequency shifts.

Abstract

We simulated the behavior of suspended carbon-nanotube (CNT) resonators over a broad range of temperatures to address the unexplained spectral broadening and frequency shifts seen in experiments. We find that thermal fluctuations induce strong coupling between resonance modes. This effect leads to spectral fluctuations which readily account for the experimentally observed quality factors $Q\sim100$ at $300\ K$. Using a mean field approach to describe entropic fluctuations we analytically calculate $Q$ and frequency shifts in tensioned and buckled CNTs and find excellent agreement with simulations.