Dissipation and fluctuations in nanoelectromechanical systems based on carbon nanotubes

TL;DR

This study investigates the dissipation and fluctuation phenomena in nanotube-based nanoelectromechanical systems, revealing how structural factors and defects influence the quality factor and energy dissipation through molecular dynamics simulations.

Contribution

It provides a quantitative analysis of factors affecting dissipation and fluctuations in nanotube NEMS, introducing new insights into their impact on the Q-factor and vibrational behavior.

Findings

Commensurability increases dissipation rate.

Wall end structure and nanotube length do not affect Q-factor.

Defects significantly decrease the Q-factor.

Abstract

Tribological characteristics of nanotube-based nanoelectromechanical systems (NEMS) exemplified by a gigahertz oscillator are studied. Various factors that influence the tribological properties of the nanotube-based NEMS are quantitatively analyzed with the use of molecular dynamics calculations of the quality factor (Q-factor) of the gigahertz oscillator. We demonstrate that commensurability of the nanotube walls can increase the dissipation rate, while the structure of the wall ends and the nanotube length do not influence the Q-factor. It is shown that the dissipation rate depends on the interwall distance and the way of fixation of the outer wall and is significant in the case of a poor fixation for the nanotubes with a large interwall distance. Defects are found to strongly decrease the Q-factor due to the excitation of low-frequency vibrational modes. No universal correlation between the static friction forces and the energy dissipation rate is established. We propose an explanation of the obtained results on the basis of the classical theory of vibrational-translational relaxation. Significant thermodynamics fluctuations are revealed in the gigahertz oscillator by molecular dynamics simulations and analyzed in the framework of the fluctuation-dissipation theorem. Possibility of designing the NEMS with a desirable Q-factor and their applications are discussed on the basis of the above results.