# Influence of defect-induced deformations on electron transport in carbon nanotubes

## TL;DR

This study uses ab-initio calculations to analyze how defect-induced long-range deformations affect electron transport in carbon nanotubes, revealing diameter-dependent impacts on conductance.

## Contribution

It demonstrates that long-range deformation significantly influences electronic transport in small-diameter CNTs, emphasizing its importance in theoretical modeling.

## Key findings

- Long-range deformation affects conductance in thin (9,0)-CNTs.
- Impact of deformation decreases with increasing CNT diameter.
- Effect varies depending on CNT and defect types.

## Abstract

We theoretically investigate the influence of defect-induced long-range deformations in carbon nanotubes on their electronic transport properties. To this end we perform numerical ab-initio calculations using a density-functional-based tight-binding (DFTB) model for various tubes with vacancies. The geometry optimization leads to a change of the atomic positions. There is a strong reconstruction of the atoms near the defect (called "distortion") and there is an additional long-range deformation. The impact of both structural features on the conductance is systematically investigated. We compare short and long CNTs of different kinds with and without long-range deformation. We find for the very thin (9,0)-CNT that the long-range deformation additionally affects the transmission spectrum and the conductance compared to the short-range lattice distortion. The conductance of the larger (11,0)- or the (14,0)-CNT is overall less affected implying that the influence of the long-range deformation decreases with increasing tube diameter. Furthermore, the effect can be either positive or negative depending on the CNT type and the defect type. Our results indicate that the long-range deformation must be included in order to reliably describe the electronic structure of defective, small-diameter zigzag tubes.