Static dielectric properties of carbon nanotubes from first principles

TL;DR

This paper uses first-principles calculations to analyze the static dielectric properties of single- and multi-wall carbon nanotubes, revealing how their polarizabilities depend on structure, size, and electronic properties.

Contribution

It provides a detailed first-principles characterization of the dielectric response of carbon nanotubes, including scaling laws and a simple electrostatic model.

Findings

Longitudinal polarizability scales as inverse square of band gap.

Transverse polarizability is proportional to the square of the effective radius.

Dielectric response remains linear at high electric fields.

Abstract

We characterize the response of isolated single- (SWNT) and multi-wall (MWNT) carbon nanotubes and bundles to static electric fields using first-principles calculations and density-functional theory. The longitudinal polarizability of SWNTs scales as the inverse square of the band gap, while in MWNTs and bundles it is given by the sum of the polarizabilities of the constituent tubes. The transverse polarizability of SWNTs is insensitive to band gaps and chiralities and is proportional to the square of the effective radius; in MWNTs the outer layers dominate the response. The transverse response is intermediate between metallic and insulating, and a simple electrostatic model based on a scale-invariance relation captures accurately the first-principles results. Dielectric response of non-chiral SWNTs in both directions remains linear up to very high values of applied field.