Modelling a spin-selective interface between ferromagnetic electrodes and a carbon nanotube—towards the enhanced giant magnetoresistance effect

The effect of interface conditions on the giant magnetoresistance (GMR) is studied. It is shown that the GMR changes drastically in the presence of extra magnetic monolayers at the ferromagnetic electrodes. The monolayers may make the spin-dependent conductance channels nearly or completely closed if they are antiferromagnetically exchange coupled to the electrodes. It is shown that the conductance spectrum of the device reflects, to a large degree, the internal band structure of the nanotube. Therefore the GMR effect is quite sensitive to the relative bands' line-up of electrodes and the nanotube and it may be tuned by a gate voltage applied to the nanotube.