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Bibliographic Details
Main Authors: Xu, Ke-Jun, Hsu, Kuan H., Giles-Donovan, Nathan, Parzyck, Christopher T., Lee, Gi-Hyeok, Yang, Wanli, Okamoto, Jun, Huang, Hsiao-Yu, Huang, Di-Jing, Kas, Joshua J., Vinson, John, Shen, Zhi-Xun, Lee, Dung-Hai, Devereaux, Thomas P., Lee, Wei-Sheng, Birgeneau, Robert J.
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.30293
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Table of Contents:
  • A Kondo insulator (KI) is a prototypical example of a highly entangled phase of matter, where many-body interactions between local moments and delocalized electrons engender the non-magnetic insulating ground state. Conventionally, the local moments arise from atomic multiplet states with a narrow bandwidth, limiting Kondo coherence to low temperatures. Here, we realize a new paradigm for constructing the KI state with hybridized molecular orbitals in FeSb2. Resonant inelastic X-ray scattering (RIXS) at the Fe L-edge reveals distinct signatures of band-like continuum states and localized states. Comparisons with first-principles calculations establish a mixed-configuration ground state with hybridized Fe d-Sb p molecular orbitals as basis states. By systematically investigating the RIXS momentum, temperature, and doping dependences, we find propagating collective modes commensurate with many-body charge and spin excitations. Our results pave the way for understanding the emerging class of unconventional d electron insulators and engineering high temperature Kondo many-body states.