Photon-assisted transport in a carbon nanotube

TL;DR

This paper studies how external radiation influences quantum transport in a carbon nanotube, revealing conductance enhancements, oscillations, and steps that depend on radiation frequency and intensity, providing insights into nanotube energy spectra.

Contribution

It introduces a detailed analysis of photon-assisted transport in carbon nanotubes, highlighting how radiation parameters affect conductance and spectral features.

Findings

Conductance can be enhanced or suppressed by external radiation.

Oscillations in conductance depend strongly on radiation frequency.

Low-energy radiation induces step-like features in conductance.

Abstract

We investigate the quantum transport through a single-wall carbon nanotube connected to leads in the presence of an external radiation field. We analyze the conductance spectrum as a function of the frequency and strength of the field. We found that above a critical value of the field intensity, an enhancement of the conductance, or suppressed resistance, as a function of the field strength occurs. The conductance increases displaying oscillations which amplitude shows a strong dependence on the field frequency. For low radiation energies in comparison to the lead-CNT coupling energies, the oscillations evolve toward a structure of well defined steps in the conductance. We have shown that in this range of frequencies the field intensity dependence of the conductance can give direct information of single-walled carbon nanotubes energy spectra.