Effective Ionic Valence and Local Magnetic Moment in Kagome Superconductors
Abstract
In order to understand the unexpected similarity and the correlated behavior in kagome superconductor families AV3Sb5 (A = K, Rb, Cs) and ATi3Bi5 (A = Rb, Cs), we investigate the Hartree-scale local electronic structure of these systems. Our result indicates that V and Ti ions are both of 2+ valence such that the corresponding itinerant carrier densities are similar, and the difference in electron count is instead reflected in their quantum fluctuating ionic magnetic moments. However, due to the frustrated lattice geometry of these materials, such local moments are difficult to experimentally observe via standard probes. For verification, we systematically introduce nonmagnetic Sn impurities to locally relieve the geometric frustration and experimentally demonstrate the existence of well-defined local magnetic moments via magnetic susceptibility and muon spin rotation or relaxation (μSR) measurements. All experiments discover a systematic increase of magnetic susceptibility upon increasing nonmagnetic impurity level. Our discovered ionic moments suggest a paradigm shift from the existing itinerant carrier-only picture to one incorporating strong correlation from local ionic spins. The associated interatomic and local-itinerant correlations offer a solid ground for the emergence of the observed rich correlated behavior in this new family of superconducting materials.
Versions
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BibTeX
@misc{jiang2026effective,
title = {{Effective Ionic Valence and Local Magnetic Moment in Kagome Superconductors}},
author = {Ruoshi Jiang and Zi-Jian Lang and Yuzki Oey and Andrea Capa Salinas and Stephen D. Wilson and Yongwei Li and Ilya Shipulin and Yiwen Zhang and Deng Hu and Zhiwei Wang and Hans-Henning Klauss and Zurab Guguchia and Vadim Grinenko and Wei Ku},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.11927},
eprint = {2609.11927},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.11927},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Effective Ionic Valence and Local Magnetic Moment in Kagome Superconductors
AU - Ruoshi Jiang
AU - Zi-Jian Lang
AU - Yuzki Oey
AU - Andrea Capa Salinas
AU - Stephen D. Wilson
AU - Yongwei Li
AU - Ilya Shipulin
AU - Yiwen Zhang
AU - Deng Hu
AU - Zhiwei Wang
AU - Hans-Henning Klauss
AU - Zurab Guguchia
AU - Vadim Grinenko
AU - Wei Ku
PY - 2026
DA - 2026/09/10
PB - arXiv
DO - 10.48550/arxiv.2609.11927
UR - https://arxiv.org/abs/2609.11927
AB - In order to understand the unexpected similarity and the correlated behavior in kagome superconductor families AV_3Sb_5 (A = K, Rb, Cs) and ATi_3Bi_5 (A = Rb, Cs), we investigate the Hartree-scale local electronic structure of these systems. Our result indicates that V and Ti ions are both of 2+ valence such that the corresponding itinerant carrier densities are similar, and the difference in electron count is instead reflected in their quantum fluctuating ionic magnetic moments. However, due to the frustrated lattice geometry of these materials, such local moments are difficult to experimentally observe via standard probes. For verification, we systematically introduce nonmagnetic Sn impurities to locally relieve the geometric frustration and experimentally demonstrate the existence of well-defined local magnetic moments via magnetic susceptibility and muon spin rotation or relaxation (μSR) measurements. All experiments discover a systematic increase of magnetic susceptibility upon increasing nonmagnetic impurity level. Our discovered ionic moments suggest a paradigm shift from the existing itinerant carrier-only picture to one incorporating strong correlation from local ionic spins. The associated interatomic and local-itinerant correlations offer a solid ground for the emergence of the observed rich correlated behavior in this new family of superconducting materials.
ER -