Magnetization and conductance of a magnetic adatom adsorbed on single-walled carbon nanotubes

The adsorption of magnetic adatoms on nanotubes is pivotal for understanding their influence on nanotube properties and for controlling magnetic interactions at the nanoscale, with significant potential for spintronics and quantum computing applications. This study investigates the magnetic transition curves, magnetization, and conductance of magnetic adatoms adsorbed on armchair and zigzag single-walled carbon nanotubes (SWCNTs) using the Green function formalism. The magnetic transition curves depend not only on the chirality but also on the parameter n , which defines the electronic nature of the nanotubes. For armchair SWCNTs and zigzag SWCNTs where n is a multiple of 3, the curves reveal two contributions: one from the linear dispersion near the Fermi level, resembling a magnetic impurity in a metallic host, and another from bands arising due to periodic boundary conditions. Conversely, for zigzag SWCNTs with n not a multiple of 3, only the second contribution is observed. The conductance of armchair SWCNTs and zigzag SWCNTs with n multiples of 3 exhibits two peaks corresponding to the spin levels of the magnetic adatom, while for zigzag SWCNTs with n not a multiple of 3, the semiconducting nature results in a single peak if one spin energy level lies within the bandgap.