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.
|Titolo:||Charge Disproportionation, Mixed Valence, and Janus Effect in Multiorbital Systems: A Tale of Two Insulators|
|Autori:||Isidori, A.; Berovic, M.; Fanfarillo, L.; De'Medici, L.; Fabrizio, M.; Capone, M.|
|Data di pubblicazione:||2019|
|Numero di Articolo:||186401|
|Digital Object Identifier (DOI):||10.1103/PhysRevLett.122.186401|
|Appare nelle tipologie:||1.1 Journal article|