Phonon interference in the array of carbon nanotubes

TL;DR

This paper investigates phonon interference phenomena in arrays of carbon nanotubes, combining molecular dynamics and elastic shell models to analyze wave propagation and interference effects caused by array irregularities.

Contribution

It introduces a composite model for nanotube array dynamics and analytically describes phonon interference, including the effects of array irregularities on transmittance.

Findings

Phonon interference analogous to Fano resonance observed.

Analytical dispersion relations derived for nanotube arrays.

Transmittance calculations show impact of array irregularities.

Abstract

The dynamics of the one-dimensional array of the single-walled carbon nanotubes, which interact by van der Waals forces, is considered. The molecular dynamics simulation shows that both the mutual displacements of the nanotubes and the deformations of their walls occur in the low-frequency oscillations domain. The composite model taking into account both types of the nanotubes' motions was developed in the framework of the thin elastic shell theory. Such an approach allows us to reduce the problem to the dynamics of the two-parametric linear lattice with contact interaction. The dispersion relations are represented analytically and the multi-channel propagation that results to phonon interference (the acoustical analogue of the Fano resonance) is observed in the presence of the array's irregularities. The latter can be formed with redundant nanotubes, which are placed over the array in the groove between neighbour sites. The calculations of the transmittance have been performed by the transfer matrix method for several typical configurations.