Conductance of carbon nanotubes with disorder: A numerical study

TL;DR

This study investigates how disorder affects the conductance of carbon nanotubes using numerical simulations, revealing that weak disorder minimally impacts conductance near the band center, while strong disorder creates a transmission gap.

Contribution

Developed a numerical method to compute conductance in disordered carbon nanotubes, analyzing effects of weak and strong disorder on electronic transmission.

Findings

Weak disorder has little effect near the band center.

Conductance dips near second subband minima.

Strong disorder induces a transmission gap.

Abstract

We study the conductance of carbon nanotube wires in the presence of disorder, in the limit of phase coherent transport. For this purpose, we have developed a simple numerical procedure to compute transmission through carbon nanotubes and related structures. Two models of disorder are considered, weak uniform disorder and isolated strong scatterers. In the case of weak uniform disorder, our simulations show that the conductance is not significantly affected by disorder when the Fermi energy is close to the band center. Further, the transmission around the band center depends on the diameter of these zero bandgap wires. We also find that the calculated small bias conductance as a function of the Fermi energy exhibits a dip when the Fermi energy is close to the second subband minima. In the presence of strong isolated disorder, our calculations show a transmission gap at the band center, and the corresponding conductance is very small.