Negative Differential Conductivity in Carbon Nanotubes in the Presence of an External Electric Field

TL;DR

This paper theoretically investigates electron transport in carbon nanotubes under external electric fields, predicting negative differential conductivity and its potential for terahertz radiation generation without instability.

Contribution

It introduces a theoretical model predicting negative differential conductivity in carbon nanotubes under specific electric field conditions, with implications for terahertz source development.

Findings

Negative differential conductivity occurs when ωτ<<1.

Peak conductivity decreases as AC field amplitude increases.

Potential for terahertz radiation generation without instability.

Abstract

We study theoretically the electron transport properties in carbon nanotubes under the influence of an external electric field E(t) using Boltzmann's equation. The current-density equation is derived. Negative differential conductivity is predicted when {\omega}{\tau}<<1 (quasi-static case). We observed this in the neighbourhood where the constant electric field E_o is equal to the amplitude of the AC electric field E_1 and the peak decreases with increasing E_1. This phenomenon can also be used for the generation of terahertz radiation without electric current instability.