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arXiv · 2505.21675

Interplay between Hund's rule and Kondo effect in a quantum dot

Olfa Dani·Johannes C. Bayer·Timo Wagner·Gertrud Zwicknagl·Rolf J. Haug
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Abstract

The interaction between localized spins on a quantum dot and free electrons in the reservoirs forms a many-particle entangled system giving rise to the Kondo effect. Here, we investigate electron transport in the third shell of a gate-defined GaAs quantum dot. The addition energy shows a maximum at half-filling of the shell which can be described analytically with Hund's rule exchange interaction. For 7 to 11 electrons occupying the quantum dot Zero-bias anomalies characteristic for the Kondo effect are observed, but with unexpected widths. Here the quantum dot has to be described as a multi-orbital Kondo impurity with Hund's interaction. In this way this quantum dot can be seen as a model system for a Hund's coupled mixed-valence quantum impurity as appearing in Hund's metals where local ferromagnetic interactions between orbitals lead to the emergence of complex electronic states.

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Olfa Dani, Johannes C. Bayer, Timo Wagner, Gertrud Zwicknagl, Rolf J. Haug. 2025-05-27. Interplay between Hund's rule and Kondo effect in a quantum dot. https://arxiv.org/abs/2505.21675

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