SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Complex Oxides
TT 30.4: Talk
Wednesday, March 29, 2023, 10:15–10:30, HSZ 204
Orbital imaging of the spin state transition in LaCoO3 — Brett Leedahl1, Daisuke Takegami1, Martin Sunderamnn1,2, Hlynur Gretarsson1,2, Alexander Komarek1, Arata Tanaka3, Maurits Haverkort4, and •Liu Hao Tjeng1 — 1MPI-CPfS, Dresden, Germany — 2DESY/PETRA-III, Hamburg, Germany — 3Department of Quantum Matter, Hiroshima University, Japan — 4Institute for Theoretical Physics, Heidelberg University, Germany
Here we have investigated the Co 3d orbital occupation in LaCoO3 across the spin state transition using the recently developed x-ray-based orbital-imaging method. The images collected allow for a direct determination of the amount of the Co t2g and eg holes. We find that, at the lowest temperatures, the low-spin state with the nominally t2g6eg0 electron configuration does have holes in the t2g subshell which we attribute to the presence of spin-orbit interaction. The hole amount, however, sets limits to the minimum energy gap between the lattice-frozen low-spin and high-spin states. At high temperatures, we find that the high-spin state occupation is about half (!) of the value reported in the most recent literature. Implications for the ab-initio modeling of the spin-state transition process are discussed.