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Dirk Morr
Kondo physics at the nanoscale

Location: Fachbereich Physik, FB-Raum
Time: Thursday 13.12.2007, 14h c.t.

Recent experimental advances have made it possible to study the Kondo effect in nanoscale structures. These achievements are of great importance because they allow us to manipulate the Kondo screening of single magnetic impurities, and provide the unique opportunity to study how Kondo screening and coherence evolve on different lengthscales from a single Kondo-impurity to the Kondo-lattice. In this talk, I present two examples of new quantum effects that arise in such nanostructures.

First, I demonstrate that the creation of electronic eigenmodes in a nanostructure leads to unconventional Kondo-behavior. In particular, the Kondo-temperature, TK, of a magnetic impurity located inside the nanostructure varies with the impurity's location and is determined by the eigenmodes' spatial structure. Moreover, the modes' frequency dependence leads to a linear relation between TK and the local density of states, in stark contrast to the conventional Kondo-effect. Second, I consider the emergence of Kondo screening in finite size Kondo lattices, so-called Kondo droplets. I show that (a) the strength of the screening, as measured by the hybridization, and (b) the coherent coupling of the Kondo resonances, can be resonantly enhanced, or suppressed by via changes in the droplet's geometry and size.

More information: F. von Oppen (vonoppenphysik.fu-berlin.de)

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