Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 61: Correlated Electrons: (General) Theory 2

TT 61.3: Vortrag

Donnerstag, 23. März 2017, 10:00–10:15, HSZ 204

Site-selective Mott insulator-metal transition and charge disproportionation in Fe₂O₃ under pressure — •Ivan Leonov — Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany — Materials Modeling and Development Laboratory, National University of Science and Technology ’MISIS’, 119049 Moscow, Russia

We present a theoretical study of the electronic structure and phase stability of hematite (α-Fe₂O₃) near a pressure-induced Mott insulator-metal transition using the fully charge self-consistent DFT+DMFT approach. Our results reveal that upon compression above ∼ 45 GPa, Fe₂O₃ undergoes a Mott insulator (MI) to site-selective MI phase transition. The latter is characterized by a collapse of local magnetic moments and emergence of a metallic state only on half of the Fe sites. Our results suggest that the phase transition is accompanied a charge disproportionation of the Fe ions, implying a complex interplay between electronic correlations and the lattice. We explain the high-pressure behavior of Fe₂O₃ and suggest that it is primary a localized to itinerant moment behavior transition that gives rise to magnetic collapse of the Fe ions under pressure.