  We present an approach for calculating the electronic structure and transport
properties of nanoscopic conductors that takes into account the dynamical
correlations of strongly interacting d- or f-electrons by combining density
functional theory calculations with the dynamical mean-field theory. While the
density functional calculation yields a static mean-field description of the
weakly interacting electrons, the dynamical mean-field theory explicitly takes
into account the dynamical correlations of the strongly interacting d- or
f-electrons of transition metal atoms. As an example we calculate the
electronic structure and conductance of Ni nanocontacts between Cu electrodes.
We find that the dynamical correlations of the Ni 3d-electrons give rise to
quasi-particle resonances at the Fermi-level in the spectral density. The
quasi-particle resonances in turn lead to Fano lineshapes in the conductance
characteristics of the nanocontacts similar to those measured in recent
experiments of magnetic nanocontacts.
