Low Energy Coherent Transport in Metallic Carbon Nanotube Junctions

TL;DR

This paper investigates the low-energy electronic transport properties of crossed metallic carbon nanotube junctions, revealing how junction asymmetries and crossing angles influence conductance and induce a zero-field Hall effect.

Contribution

It introduces a tight-binding model for tunneling between chiral nanotubes and analyzes how junction asymmetries and crossing angles affect conductance and Hall effects.

Findings

Conductance scales inversely with contact conductance.

Crossing angle is the key factor affecting conductance.

Junction asymmetries lead to a zero-field Hall conductance.

Abstract

We study the low-energy electronic properties of a junction made of two crossed metallic carbon nanotubes of general chiralities. We derive a tight binding tunneling matrix element that couples low-energy states on the two tubes, which allows us to calculate the contact conductance of the junction. We find that the intrinsic asymmetries of the junction cause the forward and backward hopping probabilities from one tube to another to be different. This defines a zero-field Hall conductance for the junction, which we find to scale inversely with the junction contact conductance. Through a systematic study of the dependence of the junction conductance on different junction parameters, we find that the crossing angle is the dominant factor which determines the magnitude of the conductance.