The effect of vacancy-induced magnetism on electronic transport in armchair carbon nanotubes

TL;DR

This study investigates how vacancy-induced magnetic moments affect electron transport in metallic single-wall carbon nanotubes, revealing spin polarization effects and the potential for controlling electron spin via gate voltage.

Contribution

It introduces a detailed theoretical analysis of magnetic moments around vacancies and their impact on electronic transport in carbon nanotubes, using the Landauer formalism and Hubbard model.

Findings

Magnetic moments around vacancies induce spin-polarized electron conduction.

Vacancy geometry significantly influences electron scattering and transport.

Gate voltage can enhance electron-spin polarization in the system.

Abstract

The influence of local magnetic moment formation around three kinds of vacancies on the electron conduction through metallic single-wall carbon nanotubes is studied by use of the Landauer formalism within the coherent regime. The method is based on the single-band tight-binding Hamiltonian, a surface Green's function calculation, and the mean-field Hubbard model. The numerical results show that the electronic transport is spin-polarized due to the localized magnetic moments and it is strongly dependent on the geometry of the vacancies. For all kinds of vacancies, by including the effects of local magnetic moments, the electron scattering increases with respect to the nonmagnetic vacancies case and hence, the current-voltage characteristic of the system changes. In addition, a high value for the electron-spin polarization can be obtained by applying a suitable gate voltage.