Charge disproportionation, mixed valence, and Janus effect in multiorbital systems: A tale of two insulators
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.
Keywords
Cite
@article{arxiv.1810.01899,
title = {Charge disproportionation, mixed valence, and Janus effect in multiorbital systems: A tale of two insulators},
author = {Aldo Isidori and Maja Berovic and Laura Fanfarillo and Luca de' Medici and Michele Fabrizio and Massimo Capone},
journal= {arXiv preprint arXiv:1810.01899},
year = {2019}
}
Comments
5+4 pages, 4 figures