Kondo Effect in Artificial and Real Molecules

In this Thesis we develop a novel direction in the theory of nano-objects, i.e., structures of nanometer size in a tunnel contact with macroscopic electron reservoirs (metallic leads). In particular we elucidate the Kondo effect predicted in tunneling through triple quantum dots and sandwich-type molecules adsorbed on metallic substrate, which are referred to as trimers. The unusual dynamical symmetry of nano-objects is one of the most intriguing problems, which arise in the theory of these systems. We demonstrate that trimers possess dynamical symmetries whose realization in Kondo tunneling is experimentally tangible. Such experimental tuning of dynamical symmetries is not possible in conventional Kondo scattering. We develop the general approach to the problem of dynamical symmetries in Kondo tunneling through nano-objects and illustrate it by numerous examples of trimers in various configurations, in parallel, in series and in ring geometries.