Herbert Schoeller

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We study the Fano-Kondo effect in a closed Aharonov-Bohm (AB) interferometer which contains a single-level quantum dot and predict a frequency doubling of the AB oscillations as a signature of Kondo-correlated states. Using the Keldysh formalism, the Friedel sum rule, and the numerical renormalization group, we calculate the exact zero-temperature linear(More)
We discuss electronic transport through a lateral quantum dot close to the singlet-triplet degeneracy in the case of a single conduction channel per lead. By applying the numerical renormalization group, we obtain rigorous results for the linear conductance and the density of states. A new quantum phase transition of the Kosterlitz-Thouless-type is found,(More)
– We present a simple model of electrical transport through a metal–molecule– metal nanojunction that includes charging effects as well as aspects of the electronic structure of the molecule. The interplay of a large charging energy and an asymmetry of the metal– molecule coupling can lead to various effects in non–linear electrical transport. In(More)
PACS. 73.63-b – Electronic transport in mesoscopic or nanoscale materials and structures. Abstract. – We describe single electron tunneling through molecular structures under the influence of nano-mechanical excitations. We develop a full quantum mechanical model, which includes charging effects and dissipation, and apply it to the vibrating C60 single(More)
We investigate the electrical transport through a system of benzene coupled to metal electrodes by electron tunneling. Using electronic structure calculations, a semiquantitative model for the pi electrons of the benzene is derived that includes general two-body interactions. After exact diagonalization of the benzene model the transport is computed using(More)
Coulomb blockade phenomena and quantum fluctuations are studied in meso-scopic metallic tunnel junctions with high charging energies. If the resistance of the barriers is large compared to the quantum resistance, transport can be described by sequential tunneling. Here we study the influence of quantum fluctuations. They are important when the resistance is(More)
We consider transport through a single-molecule magnet strongly coupled to metallic electrodes. We demonstrate that, for a half-integer spin of the molecule, electron and spin tunneling cooperate to produce both quantum tunneling of the magnetic moment and a Kondo effect in the linear conductance. The Kondo temperature depends sensitively on the ratio of(More)
We demonstrate that in a single molecule magnet strongly coupled to electrodes the Kondo effect involves all magnetic excitations. This Kondo effect is induced by the quantum tunneling of the magnetic moment. Importantly, the Kondo temperature TK can be much larger than the magnetic splittings. We find a strong modulation of the Kondo effect as a function(More)