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SYQT: Quantentransport auf molekularen Skalen

SYQT 2: Quantentransport auf molekularen Skalen

SYQT 2.3: Talk

Monday, March 11, 2002, 15:15–15:30, H2

Kondo Physics in Electron Transport through Atomic Break-Junctions — •Stefan Kirchner, Hans Kroha, and Peter Wölfle — Institut für Theorie der Kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe, Germany

Experiments on nanoscale break junctions are nowadays able to measure not only the total conductance but also its decomposition into individual transmission channels. Surprisingly, in several materials the total conductance is almost quantized although the transmission of each channel varies while the junction is elongated.
We argue that in those cases electron-electron interaction has to be taken into account although the material might be a ’good’ bulk metal. Including electron-electron interaction we derive a generalization of the unitarity sum rule to multiple transmission channels.
This approximate sum rule offers an explanation for the quasi-quantization of the conductance observed in experiments.