Large orbital magnetic moments in carbon nanotubes generated by resonant transport

TL;DR

This study demonstrates that resonant transport in metallic carbon nanotubes induces large loop currents due to quantum interference, leading to significant orbital magnetic moments and potential applications as molecular solenoids.

Contribution

It provides analytical and numerical evidence that resonant electron injection causes large orbital magnetic moments in carbon nanotubes, a novel quantum interference effect.

Findings

Large loop currents are induced at resonance.

These currents generate significant orbital magnetic moments.

The effect is inherent in zigzag and chiral nanotubes.

Abstract

The nonequilibrium Green's function method is used to study the ballistic transport in metallic carbon nanotubes when a current is injected from the electrodes with finite bias voltages. We reveal, both analytically and numerically, that large loop currents circulating around the tube are induced, which come from a quantum mechanical interference and are much larger than the current along the tube axis when the injected electron is resonant with a time-reversed pair of degenerate states, which are, in fact, inherent in the zigzag and chiral nanotubes. This results in large orbital magnetic moments, making the nanotube a molecular solenoid.