Peierls Instability in Carbon Nanotubes

TL;DR

This study uses an optimized hybrid functional to demonstrate Peierls distortions in small-armchair carbon nanotubes, revealing ground-state geometries that previous methods failed to detect.

Contribution

It introduces a tailored hybrid functional approach to accurately identify Peierls distortions in armchair carbon nanotubes.

Findings

Peierls distortions are present in n nanotubes with n up to 6.

Hybrid functional reveals distortions missed by local and semi-local density functionals.

Ground-state geometries show Peierls distortions consistent with polyacetylene.

Abstract

We present a first-principles study of Peierls distortions in \emph{trans}-polyacetylene, polyacene, and armchair $(n,n)$ carbon nanotubes. Our findings suggest that the ground-state geometries of armchair $(n,n)$ carbon nanotubes, with $n$ up to 6, exhibit a Peierls distortion as it is found for \emph{trans}-polyactetylene. In contrast to previous studies in which no Peierls distortion is found with conventional local and semi-local density functionals, we use a hybrid functional whose exact-exchange admixture has been specifically optimized for the problem at hand.