Search Results

Now showing 1 - 2 of 2
  • Item
    Unraveling the Orbital Physics in a Canonical Orbital System KCuF3
    (College Park, Md. : APS, 2021) Li, Jiemin; Xu, Lei; Garcia-Fernandez, Mirian; Nag, Abhishek; Robarts, H.C.; Walters, A.C.; Liu, X.; Zhou, Jianshi; Wohlfeld, Krzysztof; van den Brink, Jeroen; Ding, Hong; Zhou, Ke-Jin
    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.
  • Item
    Resonant inelastic x-ray incarnation of Young’s double-slit experiment
    (Washington : American Association for the Advancement of Science (A A A S), 2019) Revelli, A.; Moretti, Sala, M.; Monaco, G.; Becker, P.; Bohatý, L.; Hermanns, M.; Koethe, T.C.; Fröhlich, T.; Warzanowski, P.; Lorenz, T.; Streltsov, S.V.; van Loosdrecht, P.H.M.; Khomskii, D.I.; van den Brink, J.; Grüninger, M.
    Young’s archetypal double-slit experiment forms the basis for modern diffraction techniques: The elastic scattering of waves yields an interference pattern that captures the real-space structure. Here, we report on an inelastic incarnation of Young’s experiment and demonstrate that resonant inelastic x-ray scattering (RIXS) measures interference patterns, which reveal the symmetry and character of electronic excited states in the same way as elastic scattering does for the ground state. A prototypical example is provided by the quasi-molecular electronic structure of insulating Ba 3 CeIr 2 O 9 with structural Ir dimers and strong spin-orbit coupling. The double “slits” in this resonant experiment are the highly localized core levels of the two Ir atoms within a dimer. The clear double-slit-type sinusoidal interference patterns that we observe allow us to characterize the electronic excitations, demonstrating the power of RIXS interferometry to unravel the electronic structure of solids containing, e.g., dimers, trimers, ladders, or other superstructures.