Hund-driven local-itinerant duality of Eu-4f electrons in infinite-layer nickelates
Abstract
Recent discovery of reentrant superconductivity and elevated Tc in Eu-substituted infinite-layer nickelates raises a critical question concerning the nature of Eu-4f states and their potential interaction with Ni-d electrons. Here we combine density functional theory with the dynamical mean-field theory (DFT+DMFT) calculations to investigate the valence and magnetic properties of Eu-ions in the nickelate 112 structure, explicitly treating the Coulomb repulsion in both Ni-3d and Eu-4f shells. We find a three-regime evolution of the Eu-4f configuration driven by its Hund's rule coupling JH. The magnetic and mixed-valence Eu ionic state inferred by experiments only occurs for moderate JH, with coexisting local moments and strongly correlated j=7/2 quasiparticles, in contrast to the nonmagnetic state at small JH and the fully spin-polarized divalent state at large JH. This local-itinerant duality arises from an effectively hole-doped orbital-selective Mott state induced by the intra-4f charge transfer between j=5/2 and 7/2 manifolds. It not only explains the origin of the mixed-valence and local moment behaviors of the Eu-ions observed experimentally, but also predicts low-energy 4f quasiparticles that may hybridize with the Ni-3d electrons and contribute to the elevated Tc. Our work provides a basis for understanding the unusual ferromagnetic and superconducting properties of Eu-substituted infinite-layer nickelates.
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BibTeX
@misc{cao2026hunddriven,
title = {{Hund-driven local-itinerant duality of Eu-4$f$ electrons in infinite-layer nickelates}},
author = {Yingying Cao and Yi-feng Yang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23645},
eprint = {2609.23645},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23645},
}
RIS
TY - UNPB
TI - Hund-driven local-itinerant duality of Eu-4f electrons in infinite-layer nickelates
AU - Yingying Cao
AU - Yi-feng Yang
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23645
UR - https://arxiv.org/abs/2609.23645
AB - Recent discovery of reentrant superconductivity and elevated T_c in Eu-substituted infinite-layer nickelates raises a critical question concerning the nature of Eu-4f states and their potential interaction with Ni-d electrons. Here we combine density functional theory with the dynamical mean-field theory (DFT+DMFT) calculations to investigate the valence and magnetic properties of Eu-ions in the nickelate 112 structure, explicitly treating the Coulomb repulsion in both Ni-3d and Eu-4f shells. We find a three-regime evolution of the Eu-4f configuration driven by its Hund's rule coupling J_H. The magnetic and mixed-valence Eu ionic state inferred by experiments only occurs for moderate J_H, with coexisting local moments and strongly correlated j=7/2 quasiparticles, in contrast to the nonmagnetic state at small J_H and the fully spin-polarized divalent state at large J_H. This local-itinerant duality arises from an effectively hole-doped orbital-selective Mott state induced by the intra-4f charge transfer between j=5/2 and 7/2 manifolds. It not only explains the origin of the mixed-valence and local moment behaviors of the Eu-ions observed experimentally, but also predicts low-energy 4f quasiparticles that may hybridize with the Ni-3d electrons and contribute to the elevated T_c. Our work provides a basis for understanding the unusual ferromagnetic and superconducting properties of Eu-substituted infinite-layer nickelates.
ER -