Interplay of charge and spin fluctuations in a Hund's coupled impurity

TY - JOUR

T1 - Interplay of charge and spin fluctuations in a Hund's coupled impurity

AU - Drouin-Touchette, Victor

AU - König, Elio J.

AU - Komijani, Yashar

AU - Coleman, Piers

N1 - Funding Information: Acknowledgments.—VDT would like to thank Elias Walter, Seung-Sup B. Lee, Andreas Weichselbaum, Jan von Delft, Fabian Kugler, Abhishek Kumar, and Tsung-Han Lee for illuminating discussions. We also acknowledge useful discussions with Thomas Schäfer. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-FG02-99ER45790 (VDT, PC) and the Fonds de Recherche Québécois en Nature et Technologie (VDT). Publisher Copyright: © 2022 authors. Published by the American Physical Society.

PY - 2022/10

Y1 - 2022/10

N2 - In Hund's metals, the local ferromagnetic interaction between orbitals leads to an emergence of complex electronic states with large and slowly fluctuating magnetic moments. Introducing the Hund's coupled mixed-valence quantum impurity, we gain analytic insight into recent numerical renormalization group studies. We show that valence fluctuations drastically impede the development of a large fluctuating moment over a wide range of temperatures and energy, characterized by quenched orbital degrees of freedom and a singular logarithmic behavior of the spin susceptibility χsp″(ω) [ωln(ω/TKeff)2]-1, closely resembling power-law scaling χsp″(ω)∼ω-γ. Finally, we outline how such singular spin fluctuations can play an important role in generating a superconducting state through Hund's driven Cooper pairing.

AB - In Hund's metals, the local ferromagnetic interaction between orbitals leads to an emergence of complex electronic states with large and slowly fluctuating magnetic moments. Introducing the Hund's coupled mixed-valence quantum impurity, we gain analytic insight into recent numerical renormalization group studies. We show that valence fluctuations drastically impede the development of a large fluctuating moment over a wide range of temperatures and energy, characterized by quenched orbital degrees of freedom and a singular logarithmic behavior of the spin susceptibility χsp″(ω) [ωln(ω/TKeff)2]-1, closely resembling power-law scaling χsp″(ω)∼ω-γ. Finally, we outline how such singular spin fluctuations can play an important role in generating a superconducting state through Hund's driven Cooper pairing.

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U2 - https://doi.org/10.1103/PhysRevResearch.4.L042011

DO - https://doi.org/10.1103/PhysRevResearch.4.L042011

M3 - Article

SN - 2643-1564

VL - 4

JO - Physical Review Research

JF - Physical Review Research

IS - 4

M1 - L042011

ER -