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

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 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.