Spin-polarized transport in carbon nanotubes with impurities

Abstract

Impurity effects on the spin-polarized transport through armchair carbon nanotubes contacted by ferromagnetic leads are investigated theoretically. The length of the nanotube can cause on-resonance and off-resonance behaviors of the spin-coherent transport. The impurity suppresses the conductance for the on-resonance case, while it enhances the conductance for the off-resonance one. With increasing impurity strength, the tunnel magnetoresistance exhibits a maximum or minimum value for the on-resonance or off-resonance case, respectively.