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arXiv · 1008.5103

Gate-tunable split Kondo effect in a carbon nanotube quantum dot

A. Eichler·M. Weiss·C. Schönenberger
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Abstract

We show a detailed investigation of the split Kondo effect in a carbon nanotube quantum dot with multiple gate electrodes. It is found that the splitting decreases for increasing magnetic field, to result in a recovered zero-bias Kondo resonance at finite magnetic field. Surprisingly, in the same charge state, but under different gate-configurations, the splitting does not disappear for any value of the magnetic field, but we observe an avoided crossing of two high-conductance lines. We think that our observations can be understood in terms of a two-impurity Kondo effect with two spins coupled antiferromagnetically. The exchange coupling between the two spins can be influenced by a local gate, and the non-recovery of the Kondo resonance for certain gate configurations is explained by the existence of a small antisymmetric contribution to the exchange interaction between the two spins.

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A. Eichler, M. Weiss, C. Schönenberger. 2011-05-31. Gate-tunable split Kondo effect in a carbon nanotube quantum dot. https://doi.org/10.1088/0957-4484/22/26/265204

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