SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Correlated Electrons: Electronic Structure Calculations

TT 21.7: Vortrag

Dienstag, 28. März 2023, 11:00–11:15, HSZ 201

Orbital-selective metal-insulator transitions in the presence of strong magnetic fluctuations — •Evgeny Stepanov — CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France

Orbital-selective phenomena that can be realised in materials attract enormous interest. A prominent example is an orbital-selective Mott phase, where itinerant and localised electrons live in different orbitals of the same material. Since its theoretical prediction, the orbital-selective Mott transition has been intensively studied by the state-of-the-art theoretical methods that are based on local approximations to electronic correlations, namely the dynamical mean-field theory and the slave-spin approach. Nevertheless, the existence of the orbital-selective Mott phase in realistic materials is still heavily debated and has not yet been realised experimentally.

In this talk, I will show that consistently taking into account non-local magnetic fluctuations completely changes the physical picture in the Hubbard-Kanamori model, where the orbital-selective Mott transition was predicted in the framework of the local theories. I will show that upon lowering temperature the considered system undergoes the Néel transition to an ordered antiferromagnetic phase before it experiences the orbital-selective Mott transition. Importantly, the former occurs simultaneously for all orbitals, which eliminates the orbital selectivity from the metal-insulator transition. The possibility to realise an orbital selective Néel transition will also be discussed.