Interplay between Hund's rule and Kondo effect in a quantum dot
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866912399110438912 |
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| author | Dani, Olfa Bayer, Johannes C. Wagner, Timo Zwicknagl, Gertrud Haug, Rolf J. |
| author_facet | Dani, Olfa Bayer, Johannes C. Wagner, Timo Zwicknagl, Gertrud Haug, Rolf J. |
| contents | 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_21675 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Interplay between Hund's rule and Kondo effect in a quantum dot Dani, Olfa Bayer, Johannes C. Wagner, Timo Zwicknagl, Gertrud Haug, Rolf J. Mesoscale and Nanoscale Physics 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. |
| title | Interplay between Hund's rule and Kondo effect in a quantum dot |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2505.21675 |