Multiorbital Hubbard models host strongly correlated "Hund's metals" even for interactions much stronger than the bandwidth. We characterize this interaction-resilient metal as a mixed-valence state. In particular, it can be pictured as a bridge between two strongly correlated insulators: a high-spin Mott insulator and a charge-disproportionated insulator which is stabilized by a very large Hund's coupling. This picture is confirmed comparing models with negative and positive Hund's coupling for different fillings. Our results provide a characterization of the Hund's metal state and connect its presence with charge disproportionation, which has indeed been observed in chromates and proposed to play a role in iron-based superconductors.

Charge Disproportionation, Mixed Valence, and Janus Effect in Multiorbital Systems: A Tale of Two Insulators / Isidori, A.; Berovic, M.; Fanfarillo, L.; De'Medici, L.; Fabrizio, M.; Capone, M.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 122:18(2019), pp. 1-6. [10.1103/PhysRevLett.122.186401]

Charge Disproportionation, Mixed Valence, and Janus Effect in Multiorbital Systems: A Tale of Two Insulators

Isidori A.;Berovic M.;Fanfarillo L.;De'Medici L.;Fabrizio M.;Capone M.
2019

Abstract

Multiorbital Hubbard models host strongly correlated "Hund's metals" even for interactions much stronger than the bandwidth. We characterize this interaction-resilient metal as a mixed-valence state. In particular, it can be pictured as a bridge between two strongly correlated insulators: a high-spin Mott insulator and a charge-disproportionated insulator which is stabilized by a very large Hund's coupling. This picture is confirmed comparing models with negative and positive Hund's coupling for different fillings. Our results provide a characterization of the Hund's metal state and connect its presence with charge disproportionation, which has indeed been observed in chromates and proposed to play a role in iron-based superconductors.
122
18
1
6
186401
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.186401
Isidori, A.; Berovic, M.; Fanfarillo, L.; De'Medici, L.; Fabrizio, M.; Capone, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11767/98571
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