Myron Strongin Seminar Series

"Hund physics landscape of two-orbital system"

Presented by Sangkook Choi, BNL

Monday, May 10, 2021, 1:30 pm — Bldg. 734 (Virtual)

Motivated by the recent discovery of superconductivity in infinite-layer nickelates RE1−δSrδNiO2 (RE=Nd, Pr), we study the role of Hund's coupling J 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's 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's metal, and valence-skipping metal, from the effect of J being away from Mottness. Defining criteria characterizing these metals are suggested, establishing the existence of Hund's metallicity in two-orbital systems.

Hosted by: Weiguo Yin

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