Density of states for metallic carbon nanotubes with a magnetic impurity

The density of states for metallic single-walled carbon nanotubes (SWNTs) with a magnetic impurity is studied theoretically. A single-orbital Anderson model is applied to describe the magnetic impurity/SWNT system. The Green's function at zero temperature is calculated with a rapidly convergent perturbation method. A narrow peak near the Fermi level appears which is the predicted Kondo resonance induced by the interplay of the magnetic impurity and the conduction electrons of the host metal. The Kondo temperature is found to decrease with the increase of the nanotube diameter. And the Kondo resonance is very localized in real space which agrees well with the experimental results.