Anomalous Aharonov--Bohm gap oscillations in carbon nanotubes

TL;DR

This paper reveals that curvature effects and electron spill-out significantly alter the expected Aharonov-Bohm gap oscillations in carbon nanotubes, challenging previous assumptions and predicting new phenomena.

Contribution

It introduces an ab-initio approach showing that curvature and electron spill-out modify the Aharonov-Bohm effect in nanotubes, providing new insights into their electronic behavior.

Findings

Breakdown of periodicity in gap oscillations due to curvature effects

Prediction of a large metallic phase at low magnetic flux in multi-walled nanotubes

Identification of anomalous Aharonov-Bohm phenomena in semi-conductive and metallic tubes

Abstract

The gap oscillations caused by a magnetic flux penetrating a carbon nanotube represent one of the most spectacular observation of the Aharonov-Bohm effect at the nano--scale. Our understanding of this effect is, however, based on the assumption that the electrons are strictly confined on the tube surface, on trajectories that are not modified by curvature effects. Using an ab-initio approach based on Density Functional Theory we show that this assumption fails at the nano-scale inducing important corrections to the physics of the Aharonov-Bohm effect. Curvature effects and electronic density spilled out of the nanotube surface are shown to break the periodicity of the gap oscillations. We predict the key phenomenological features of this anomalous Aharonov-Bohm effect in semi-conductive and metallic tubes and the existence of a large metallic phase in the low flux regime of Multi-walled nanotubes, also suggesting possible experiments to validate our results.