2020/10/31 by Jiemin Li, Lei Xu, Mirian Garcia-Fernandez +12 · 17 citations
Materials Science · Physics and Astronomy · #Ab initio #Advanced Condensed Matter Physics #Ansatz #Atomic physics #Energy (signal processing) #Iron-based superconductors research #Physics #Quantum #Quantum mechanics #Rare-earth and actinide compounds #Spinon #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.126.106401
published in Physical Review Letters 126(10), 106401 (American Physical Society) · 6 pages, 4 figures
openalex created_date 2020/10/29 · openalex publication_date 2021/03/09 · arxiv created 2021/03/20 · arxiv updated 2021/03/23 · openalex updated_date 2026/08/06
We explore the existence of the collective orbital excitations, orbitons, in the canonical orbital system KCuF3 using the Cu L3-edge resonant inelastic x-ray scattering. We show that the nondispersive high-energy peaks result from the Cu2+ dd orbital excitations. These high-energy modes display good agreement with the ab initio quantum chemistry calculation, indicating that the dd excitations are highly localized. At the same time, the low-energy excitations present clear dispersion. They match extremely well with the two-spinon continuum following the comparison with Müller ansatz calculations. The localized dd excitations and the observation of the strongly dispersive magnetic excitations suggest that the orbiton dispersion is below the resolution detection limit. Our results can reconcile with the strong local Jahn-Teller effect in KCuF3, which predominantly drives orbital ordering.