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Title: Hundness versus Mottness in a three-band Hubbard–Hund model: On the origin of strong correlations in Hund metals

Abstract

Hund metals are multi-orbital systems with moderate Coulomb interaction, U, among charges and sizeable Hund’s rule coupling, J (< U) , that aligns the spins in different orbitals. They show strong correlation effects, like very low Fermi-liquid coherence scales and intriguing incoherent transport regimes, resulting in bad metallic behavior. But to what extent are these strong correlations governed by Mottness, i.e. the blocking of charge fluctuations close to a Mott insulator transition (MIT) induced by U, or by Hundness, a new route towards strong correlations induced by J? To answer this question, we study the full phase diagram of a degenerate three-band Hubbard–Hund model on a Bethe lattice at zero temperature using single-site dynamical mean-field theory and the numerical renormalization group as efficient real-frequency multi-band impurity solver. Hund metal behavior occurs in this minimal model for a filling close to nd = 2, moderate U and sizeable J, the “Hund-metal regime”. In particular, strong correlations manifest themselves there by an unusually low quasiparticle weight. Generalizing previous results on this model, we show that “spin–orbital separation” (SOS) is a generic Hund’s-coupling-induced feature in the whole metallic regime of the phase diagram for 1 < nd < 3 and sizeable J.

Authors:
 [1];  [2]; ORCiD logo [3];  [1]
  1. Ludwig Maximilian Univ., Munich (Germany)
  2. Rutgers Univ., Piscataway, NJ (United States)
  3. Ludwig Maximilian Univ., Munich (Germany); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1543409
Alternate Identifier(s):
OSTI ID: 1635809
Report Number(s):
BNL-211894-2019-JAAM
Journal ID: ISSN 0003-4916
Grant/Contract Number:  
SC0012704; DMR-1733071
Resource Type:
Accepted Manuscript
Journal Name:
Annals of Physics
Additional Journal Information:
Journal Volume: 405; Journal Issue: C; Journal ID: ISSN 0003-4916
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Stadler, K. M., Kotliar, G., Weichselbaum, A., and von Delft, J. Hundness versus Mottness in a three-band Hubbard–Hund model: On the origin of strong correlations in Hund metals. United States: N. p., 2018. Web. doi:10.1016/j.aop.2018.10.017.
Stadler, K. M., Kotliar, G., Weichselbaum, A., & von Delft, J. Hundness versus Mottness in a three-band Hubbard–Hund model: On the origin of strong correlations in Hund metals. United States. doi:https://doi.org/10.1016/j.aop.2018.10.017
Stadler, K. M., Kotliar, G., Weichselbaum, A., and von Delft, J. Thu . "Hundness versus Mottness in a three-band Hubbard–Hund model: On the origin of strong correlations in Hund metals". United States. doi:https://doi.org/10.1016/j.aop.2018.10.017. https://www.osti.gov/servlets/purl/1543409.
@article{osti_1543409,
title = {Hundness versus Mottness in a three-band Hubbard–Hund model: On the origin of strong correlations in Hund metals},
author = {Stadler, K. M. and Kotliar, G. and Weichselbaum, A. and von Delft, J.},
abstractNote = {Hund metals are multi-orbital systems with moderate Coulomb interaction, U, among charges and sizeable Hund’s rule coupling, J (< U) , that aligns the spins in different orbitals. They show strong correlation effects, like very low Fermi-liquid coherence scales and intriguing incoherent transport regimes, resulting in bad metallic behavior. But to what extent are these strong correlations governed by Mottness, i.e. the blocking of charge fluctuations close to a Mott insulator transition (MIT) induced by U, or by Hundness, a new route towards strong correlations induced by J? To answer this question, we study the full phase diagram of a degenerate three-band Hubbard–Hund model on a Bethe lattice at zero temperature using single-site dynamical mean-field theory and the numerical renormalization group as efficient real-frequency multi-band impurity solver. Hund metal behavior occurs in this minimal model for a filling close to nd = 2, moderate U and sizeable J, the “Hund-metal regime”. In particular, strong correlations manifest themselves there by an unusually low quasiparticle weight. Generalizing previous results on this model, we show that “spin–orbital separation” (SOS) is a generic Hund’s-coupling-induced feature in the whole metallic regime of the phase diagram for 1 < nd < 3 and sizeable J.},
doi = {10.1016/j.aop.2018.10.017},
journal = {Annals of Physics},
number = C,
volume = 405,
place = {United States},
year = {2018},
month = {11}
}

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Works referencing / citing this record:

Signatures of Mottness and Hundness in archetypal correlated metals
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Doping-driven metal-insulator transition in correlated electron systems with strong Hund's exchange coupling
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Orbital differentiation in Hund metals
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Strongly Correlated Materials from a Numerical Renormalization Group Perspective: How the Fermi-Liquid State of Sr 2 RuO 4 Emerges
journal, January 2020