Aharonov-Bohm differential conductance modulation in defective metallic single-wall carbon nanotubes

TL;DR

This paper investigates how Aharonov-Bohm flux modulates the conductance in defective metallic single-wall carbon nanotubes, revealing controllable interference patterns that could enable magneto-conductance switching devices.

Contribution

It introduces a perturbative approach to analyze the AB flux effects on conductance, demonstrating control over interference patterns in defective metallic nanotubes.

Findings

CBSIP is modulated by magnetic flux with phase shifts.

Extrema and zeros of CBSIP occur at irrational flux fractions.

Spacing between conductance extrema decreases with increasing magnetic field.

Abstract

Using a perturbative approach, the effects of the energy gap induced by the Aharonov-Bohm (AB) flux on the transport properties of defective metallic single-walled carbon nanotubes (MSWCNTs) are investigated. The electronic waves scattered back and forth by a pair of impurities give rise to Fabry-Perot oscillations which constitutes a coherent backscattering interference pattern (CBSIP). It is shown that, the CBSIP is aperiodically modulated by applying a magnetic field parallel to the nanotube axis. In fact, the AB-flux brings this CBSIP under control by an additional phase shift. As a consequence, the extrema as well as zeros of the CBSIP are located at the irrational fractions of the quantity $\Phi_\rho={\Phi}/{\Phi_0}$, where $\Phi$ is the flux piercing the nanotube cross section and $\Phi_{0}=h/e$ is the magnetic quantum flux. Indeed, the spacing between two adjacent extrema in the magneto-differential conductance (MDC) profile is decreased with increasing the magnetic field. The faster and higher and slower and shorter variations is then obtained by metallic zigzag and armchair nanotubes, respectively. Such results propose that defective metallic nanotubes could be used as magneto-conductance switching devices based on the AB effect.