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Unraveling the orbital physics in a canonical orbital system KCuF3

DOI: 10.1103/PhysRevLett.126.106401 DOI Help

Authors: J. Li (Diamond Light Source; Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences) , L. Xu (IFW Dresden) , M. Garcia-Fernandez (Diamond Light Source) , A. Nag (Diamond Light Source) , H. C. Robarts (University of Bristol; Diamond Light Source) , A. C. Walters (Diamond Light Source) , X. Liu (ShanghaiTech University) , J. Zhou (University of Texas at Austin) , K. Wohlfeld (University of Warsaw) , J. Van Den Brink (IFW Dresden; TU Dresden) , H. Ding (Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences) , K.-J. Zhou (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review Letters , VOL 126

State: Published (Approved)
Published: March 2021

Open Access Open Access

Abstract: We explore the existence of the collective orbital excitations, orbitons, in the canonical orbital system KCuF 3 using the Cu L 3 -edge resonant inelastic x-ray scattering. We show that the nondispersive high-energy peaks result from the Cu 2 +     d d orbital excitations. These high-energy modes display good agreement with the ab initio quantum chemistry calculation, indicating that the d d 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 d d 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 KCuF 3 , which predominantly drives orbital ordering.

Journal Keywords: Orbital order; Physical Systems; Mott insulators; Crystal-field theory; Resonant inelastic x-ray scattering

Subject Areas: Materials, Physics

Instruments: I21-Resonant Inelastic X-ray Scattering (RIXS)

Other Facilities: ISIS

Added On: 10/03/2021 08:40


Discipline Tags:

Quantum Materials Hard condensed matter - electronic properties Physics Materials Science

Technical Tags:

Scattering Resonant Inelastic X-ray Scattering (RIXS)