Electron properties of Carbon nanotubes in the field effect regime

TL;DR

This paper investigates how transverse electric fields significantly alter the electronic properties of Carbon nanotubes, including Fermi velocity and energy gap, through a universal screening mechanism linked to the pi electron band.

Contribution

It introduces a theoretical framework connecting electric field effects on nanotubes with the chiral anomaly and provides a universal screening function based on the pi electron band.

Findings

Reversal of Fermi velocity in metallic nanotubes under strong fields

Sign change of effective mass in semiconducting nanotubes

Universal screening function derived from pi electron band

Abstract

Electron properties of Carbon nanotubes can change qualitatively in a transverse electric field. In metallic tubes the sign of Fermi velocity can be reversed in a sufficiently strong field, while in semiconducting tubes the effective mass can change sign. These changes in the spectrum manifest themselves in a breakup of the Fermi surface and in the energy gap suppression, respectively. The effect is controlled by the field inside the tube which is screened due to the polarization induced on the tube. The theory of screening links it with the chiral anomaly for 1D fermions and obtains a universal screening function determined solely by the Carbon pi electron band.