SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Complex Oxides
TT 30.7: Talk
Wednesday, March 29, 2023, 11:00–11:15, HSZ 204
Imaging the orbital-switching in Ti2O3 across the metal-insulator transition — •Paulius Dolmantas1, Chun-Fu Chang1, Martin Sundermann1,2, Brett Leedahl1, Andrea Amorese1, Hlynur Gretarsson1,2, Alexander Komarek1, Arata Tanaka3, Maurits W. 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
Using the recently developed x-ray-based orbital-imaging method, we have been able to observe a switching of the Ti 3d orbital occupation across the metal-insulator transition in Ti2O3. We find that in the insulating state only the a1g of the t2g subshell is occupied, while in the metallic state also the egπ gets filled at the expense of the a1g. The insulator-metal transition may then be viewed as a transition from a solid of isolated Ti-Ti c-axis singlet dimers into a solid of electronically partially broken dimers, where the Ti ions acquire additional hopping in the a-b plane via the egπ channel. These findings have implications for the ab-initio modeling of the metal-insulator transition.