The Kondo Effect in Single Wall Carbon Nanotubes with Ferromagnetic Contacts

Since its first observation the Kondo effect has been a continuous drive for both theoretical and experimental physics and has seen an unprecedented renewed interest in the last years due to its observation in quantum dots. This work investigates the implications of ferromagnetic contacts (PdNi) for the transport properties in general and for the Kondo effect in particular. Despite the presence of the ferromagnetic leads, Kondo correlations are still possible. In contrast to a zero bias Kondo peak, the resonance peaks of the differential conductance are now at finite bias voltages. The reason for that is that the charge fluctuations between the quantum dot and the contacts renormalize the discrete states of the quantum dot in a spin dependent way. Intuitive formulas for the amount of splitting and its dependence on the level position are derived. Additionally, the scaling properties show that the tunneling induced exchange field influences the level structure and such the Kondo effect exactly in the same way as an external magnetic field.