Hund Physics Landscape of Two-Orbital Systems

2020/08/31 by Siheon Ryee, Myung Joon Han, Sangkook Choi · 22 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Chemistry #Condensed matter physics #Coulomb #Coupling (piping) #Electron #Hubbard model #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Materials science #Metal #Metallicity #Mott insulator #Non-blocking I/O #Physics #Quantum mechanics #Superconductivity #Valence (chemistry) #cond-mat.str-el

paper · pdf · doi:10.1103/physrevlett.126.206401

published in Physical Review Letters 126(20), 206401 (American Physical Society)

arxiv created 2021/02/10 · openalex publication_date 2021/05/17 · arxiv updated 2021/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Motivated by the recent discovery of superconductivity in infinite-layer nickelates RE_1-δSr_δNiO₂ (RE=Nd, Pr), we study the role of Hund 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 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 J being away from Mottness. Defining criteria characterizing these metals is suggested, establishing the existence of Hund metallicity in two-orbital systems.

Citations

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