# Quantum localization and electronic transport in covalently functionalized carbon nanotubes

## TL;DR

This study investigates how covalent functionalization affects quantum localization and electronic transport in metallic carbon nanotubes, revealing that adsorbates can significantly reduce localization length and alter conduction mechanisms.

## Contribution

It provides a detailed analysis of localization behavior in functionalized carbon nanotubes, highlighting the impact of different adsorbates on transport properties.

## Key findings

- Localization length decreases to 20-50 nm at 1% adsorbate concentration.
- Functionalization can switch transport from metallic to insulating behavior.
- Resonant and non-resonant adsorbates have distinct effects on localization.

## Abstract

Carbon nanotubes are of central importance for applications in nano-electronics thanks to their exceptional transport properties. They can be used as sensors, for example in biological applications, provided that they are functionalized to detect specific molecules. Due to their one-dimensional geometry the carbon nanotubes are very sensitive to the phenomenon of Anderson localization and it is therefore essential to know how the functionalization modifies their conduction properties and if they remain good conductors. Here we present a study of the quantum localization induced by functionalization in metallic single walled carbon nanotubes (SWCNT) with circumferences up to $ 15\; nm $. We consider resonant and non-resonant adsorbates that represent two types of covalently functionalized groups with moderate and strong scattering properties. The present study provides a detailed analysis of the localization behaviour and shows that the localization length can decrease down to $ 20-50\; nm $ at concentrations of about 1 percent of adsorbates. On this basis we discuss the possible electronic transport mechanisms which can be either metallic like or insulating like with variable range hopping.