I will speak about our recent first principles studies on magnetism and electron transport in different nanosystems, mainly concentrating on two examples: i) bimetallic Ni/Au/Ni nanojunctions and ii) single magnetic impurities (Ni, Co, or Fe atoms) on Au nanowires and carbon nanotubes. The first system represents a classical set-up for studying magnetoresistance (MR) where the standard density functional theory (DFT) is expected to work well. We are especially interested here in the dependence of MR on dimensionality of the junction – from 2D planar interfaces to 1D nanowires and nanocontacts. The second system, on the contrary, represents a classical set-up for the Kondo problem, where a single magnetic impurity is coupled to a nonmagnetic conductor.
The many-body effects are expected to play here an important role, screening the impurity magnetic moment at low temperatures and modifying significantly the electrical conductance. We study these phenomena combining our DFT approach with the subsequent Numerical Renormalization Group solution of appropriate Anderson model.
All our DFT calculations were carried out with a plane wave package {tt Quantum-ESPRESSO} (www.quantum-espresso.org). I will therefore discuss it in a more detail and will also say few words about other electronic structure codes available around.
IRAMIS/SPCSI