Anderson localization in carbon nanotubes: defect density and temperature effects

TL;DR

This study investigates how defects and temperature influence electrical conductance in single-walled carbon nanotubes, revealing that defects induce Anderson localization and temperature affects conductance fluctuations.

Contribution

It provides a first-principles analysis of defect and temperature effects on conductance, highlighting the transition to Anderson localization with defect density.

Findings

Di-vacancies significantly alter conductance channels.

Strong Anderson localization occurs with 5-9 defects.

Low temperatures smooth conductance fluctuations without destroying localization.

Abstract

The role of irradiation induced defects and temperature in the conducting properties of single-walled (10,10) carbon nanotubes has been analyzed by means of a first-principles approach. We find that di-vacancies modify strongly the energy dependence of the differential conductance, reducing also the number of contributing channels from two (ideal) to one. A small number of di-vacancies (5-9) brings up strong Anderson localization effects and a seemly universal curve for the resistance as a function of the number of defects. It is also shown that low temperatures, around 15-65 K, are enough to smooth out the fluctuations of the conductance without destroying the exponential dependence of the resistivity as a function of the tube length.