Orbital-specific Itinerancy and Localization in a Kagome Magnet

Fuente: arXiv
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Main Authors: Streltsov, S. V., Huang, H. Y., Ushakov, A., Wu, C. I., Singh, A., Su, J., Okamoto, J., Chen, C. T., Wang, K., Poteryaev, A. I., Cheong, S-W., Fujimori, A., Huang, D. J.
Format: Preprint
Published: 2026
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author Streltsov, S. V.
Huang, H. Y.
Ushakov, A.
Wu, C. I.
Singh, A.
Su, J.
Okamoto, J.
Chen, C. T.
Wang, K.
Poteryaev, A. I.
Cheong, S-W.
Fujimori, A.
Huang, D. J.
author_facet Streltsov, S. V.
Huang, H. Y.
Ushakov, A.
Wu, C. I.
Singh, A.
Su, J.
Okamoto, J.
Chen, C. T.
Wang, K.
Poteryaev, A. I.
Cheong, S-W.
Fujimori, A.
Huang, D. J.
contents The kagome lattice naturally hosts flat bands, Dirac fermions, and van Hove singularities, yet whether its geometry can stabilize orbital-selective phases - a hallmark of Hund's physics in multi-orbital correlated systems - has remained an open question. Here, we combine resonant inelastic X-ray scattering with density functional theory and dynamical mean-field theory to demonstrate that YMn$_6$Sn$_6$ exhibits a spontaneous orbital differentiation into coexisting itinerant and localized electrons within the same Mn $3d$ manifold. Orbitals directed along Mn-Mn bonds provide coherent quasiparticles and metallic bands, while those pointing toward ligands become strongly correlated and display non-Fermi-liquid behavior. Hund's intra-atomic exchange suppresses orbital fluctuations, stabilizing this dichotomy and providing a natural double-exchange-like mechanism for the observed ferromagnetic bilayer coupling. Our work establishes YMn$_6$Sn$_6$ as a kagome platform where orbital selectivity, flat-band topology, and Hund's metallicity converge - revealing that geometric frustration and correlation-driven orbital differentiation can cooperatively design exotic quantum phases beyond the canonical paradigms of Mott physics or band topology alone.
format Preprint
id arxiv_https___arxiv_org_abs_2603_21203
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Orbital-specific Itinerancy and Localization in a Kagome Magnet
Streltsov, S. V.
Huang, H. Y.
Ushakov, A.
Wu, C. I.
Singh, A.
Su, J.
Okamoto, J.
Chen, C. T.
Wang, K.
Poteryaev, A. I.
Cheong, S-W.
Fujimori, A.
Huang, D. J.
Strongly Correlated Electrons
Materials Science
The kagome lattice naturally hosts flat bands, Dirac fermions, and van Hove singularities, yet whether its geometry can stabilize orbital-selective phases - a hallmark of Hund's physics in multi-orbital correlated systems - has remained an open question. Here, we combine resonant inelastic X-ray scattering with density functional theory and dynamical mean-field theory to demonstrate that YMn$_6$Sn$_6$ exhibits a spontaneous orbital differentiation into coexisting itinerant and localized electrons within the same Mn $3d$ manifold. Orbitals directed along Mn-Mn bonds provide coherent quasiparticles and metallic bands, while those pointing toward ligands become strongly correlated and display non-Fermi-liquid behavior. Hund's intra-atomic exchange suppresses orbital fluctuations, stabilizing this dichotomy and providing a natural double-exchange-like mechanism for the observed ferromagnetic bilayer coupling. Our work establishes YMn$_6$Sn$_6$ as a kagome platform where orbital selectivity, flat-band topology, and Hund's metallicity converge - revealing that geometric frustration and correlation-driven orbital differentiation can cooperatively design exotic quantum phases beyond the canonical paradigms of Mott physics or band topology alone.
title Orbital-specific Itinerancy and Localization in a Kagome Magnet
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2603.21203