Coordination Complex extensions of Dynamical Mean-Field Theory for (negative) Charge Transfer Transition Metal Oxides
Final Report Abstract
The main objective of this project was the application of Dynamical Mean-Field Theory to material realistic models for transition metal oxides (TMOs) which explicitly included oxygen p-orbitals. So called charge transfer TMOs, such as high-temperature superconducting cuprates and the recently discovered superconducting nickelates, exhibit complex electronic states significantly influenced by the hybridization of transition metal d- and oxygen p-orbitals. Our central hypothesis was that explicitly including these oxygen orbitals can be crucial for making realistic predictions of both ground and excited states, as well as their tunability by external parameters. Our research employed DMFT along with its real space cluster extension (CDMFT) and the diagrammatic Dynamical Vertex Approximations (DΓA). A key part of the project involved comparing effective d-only models with more comprehensive dp-models (Emery model) explicitly incorporating oxygen p-orbitals. Our findings demonstrate that explicitly treating oxygen orbitals significantly improves predictions even within simple single-site DMFT calculations. For cuprates, using the Emery model, we successfully reproduced a realistic, non-Curie-like temperature dependence of magnetic susceptibility that closely matches experimental nuclear magnetic resonance (NMR) observations. However, detailed spectral investigations, particularly within the pseudogap regime of cuprates, revealed limitations of simple DMFT approaches, necessitating the use of advanced DΓA methods to accurately describe the momentum-selective suppression of the Fermi surface. Another major focus of our project was the extensive study of LaNiO3 , facilitated by intensive collaboration with experimental partners at the Max Planck Institute for Chemical Physics of Solids in Dresden. Our work showed that both electronic correlations and structural distortions must be explicitly accounted for in DFT+DMFT calculations to achieve good agreement with comprehensive experimental ARPES data. Key methodological advancements included implementing an unfolding scheme for correlated spectral functions, greatly enhancing and facilitating comparisons with experimental data. Finally, the TPRF (Two-Particle Response Functions) software package was significantly extended during the project and made publicly available, providing powerful computational tools for future studies of correlated electron systems.
Publications
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Interorbital singlet pairing in Sr₂RuO₄ : A Hund's superconductor. Physical Review B, 105(15).
Käser, Stefan; Strand, Hugo U. R.; Wentzell, Nils; Georges, Antoine; Parcollet, Olivier & Hansmann, Philipp
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Distinct spin and orbital dynamics in Sr2RuO4. Nature Communications, 14(1).
Suzuki, H.; Wang, L.; Bertinshaw, J.; Strand, H. U. R.; Käser, S.; Krautloher, M.; Yang, Z.; Wentzell, N.; Parcollet, O.; Jerzembeck, F.; Kikugawa, N.; Mackenzie, A. P.; Georges, A.; Hansmann, P.; Gretarsson, H. & Keimer, B.
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TRIQS/TPRF: Version 3.2.1
N. Wentzell, H. U. R. Strand, S. Käser, Y. In’t Veld, D. Simon, A. Hampel, M. Rösner, Egcpvanloon, O. Parcollet, O. Gingras, D. Philipp, T. Hahn & M. Zingl
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Single-particle spectra and magnetic susceptibility in the Emery model: A dynamical mean-field perspective. SciPost Physics, 18(5).
Tseng, Yi-Ting; Malcolms, Mario; Menke, Henri; Klett, Marcel; Schäfer, Thomas & Hansmann, Philipp
