Hund Physics Landscape of Two-Orbital Systems
ORAL
Abstract
Motivated by the recent discovery of superconductivity in infinite-layer nickelates, we study the role of Hund coupling in a quarter-filled two-orbital Hubbard model, which has been on the periphery of the attention. A region of negative effective Coulomb interaction of this model is revealed to be differentiated from three- and five-orbital models in their typical Hund metal active fillings. We identify distinctive regimes including four different correlated metals, one of which stems from the proximity to a Mott insulator, while the other three, which we call "intermediate" metal, weak Hund metal, and valence-skipping metal, from the effect of Hund coupling being away from Mottness. Defining criteria characterizing these metals is suggested, establishing the existence of Hund metallicity in two-orbital systems.
*S. R. and M. J. H. were supported by Creative Materials Discovery Program through NRF (2018M3D1A1058754) and Basic Science Research Program (2018R1A2B- 2005204). S. C. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences as a part of the Computational Materials Science Program. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231.
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Publication: [1]S. Ryee, M. J. Han, and S. Choi, Hund Physics Landscape of Two-Orbital Systems, Phys. Rev. Lett. 126, 206401 (2021).
Presenters
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Sangkook Choi
- Brookhaven National Laboratory