Oscillating chiral currents in nanotubes: a route to nanoscale magnetic test tubes

TL;DR

This paper analytically investigates chiral electron currents in carbon nanotubes, revealing oscillatory behaviors and identifying optimal chiral angles for maximizing internal magnetic fields relevant to nanoscale magnetic devices.

Contribution

It provides analytical insights into chiral current behaviors in CNTs, highlighting optimal chiral angles for magnetic field generation and potential spintronic applications.

Findings

Chiral currents oscillate and can change sign with energy.

Maximum transverse velocity occurs at 18° chiral angle.

Generated magnetic fields are sufficient for spintronic effects.

Abstract

With a view to optimising the design of carbon-nanotube (CNT) windmills and to maximising the internal magnetic field generated by chiral currents, we present analytical results for the group velocity components of an electron flux through chiral carbon nanotubes. Chiral currents are shown to exhibit a rich behaviour and can even change sign and oscillate as the energy of the electrons is increased. We find that the transverse velocity and associated angular momentum of electrons is a maximum for non-metallic CNTs with a chiral angle of 18$^o$. Such CNTs are therefore the optimal choice for CNT windmills and also generate the largest internal magnetic field for a given longitudinal current. For a longitudinal current of order $10^{-4}$ amps, this field can be of order $10^{-1}$Teslas, which is sufficient to produce interesting spintronic effects and a significant contribution to the self inductance.