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TT: Fachverband Tiefe Temperaturen

TT 106: Complex Oxides: Bulk Properties, Surfaces and Interfaces (joint session TT/MA/KFM)

TT 106.11: Vortrag

Freitag, 16. März 2018, 12:15–12:30, H 0110

Excitonic dispersion of intermediate-spin state in LaCoO₃ revealed by resonant inelastic X-ray scattering — •atsushi hariki¹, ru-pan wang², andrii sotnikov¹, federica frati², jun okamoto³, hsiao-yu huang³, amol singh³, di-jing huang³, keisuke tomiyasu⁴, chao-hung du⁵, frenk m. f de groot¹, and jan Kuneš² — ¹Institute for Solid State Physics, TU Wien, Austria — ²Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands — ³Condensed Matter Physics Group, National Synchrotron Radiatiation Research Center, Taiwan, — ⁴Department of Physics, Tohoku University, Sendai, Japan — ⁵Department of Physics, Tamkang University, New Taipei City, Taiwan,

We perform Co L-edge resonant inelastic X-ray scattering of LaCoO₃ at 20 K. We observe a dispersive state with an energy shift from 480 to 290 meV as a function of momentum from q = (0, 0, 0.26π) to q = (0, 0, 0.90π). This dispersion is attributed to the mobility of the intermediate-spin (IS) state, which is viewed as an exciton. A theoretical calculation considering the excitonic dispersion of the IS state on the background of the low-spin (LS) state supports the interpretation. The present result suggests that the mobility pushes the IS state into play to the thermal spin-state transition of LaCoO₃ in addition to the (immobile) high-spin and LS states with lower atomic-multiplet energies, as suggested by recent theoretical studies [1].
A. Sotnikov and J. Kuneš, Sci. Rep. 6, 30510 (2016).