FAIRmat Seminar with Thomas Schäfer

Thomas Schäfer, Max Planck Institute for Solid State Research will speak about
Multi-method, multi-messenger approaches to models of strong correlations
in a special FAIRmat seminar on November 24, 2022 at 10:00 CET.

Location: Erwin-Schrödinger-Zentrum, Humboldt-Universität zu Berlin (Rudower Chaussee 26, 12489 Berlin) Room 0'119 and on Zoom

The Hubbard model is the paradigmatic model for electronic correlations. In this talk I present a general framework for the reliable calculation of its properties, which we coined 'multi-method, multi-messenger' approach. I will illustrate the power of this approach with three recent studies: (i) an extensive synopsis of arguably all available finite-temperature methods for the half-filled Hubbard model on a simple square lattice in its weak-coupling regime [1] and (ii) a complementary subset of those applied to the Hubbard model on a triangular geometry [2]. While the former example fully clarifies the impact of spin fluctuations and tracks it footprints on the one- and two-particle level, the latter exhibits the intriguing interplay of geometric frustration (magnetism) and strong correlations (Mottness). As a last example, (iii) I will show the application to a model system for the magnetic properties of an actual material, the infinite layer nickelate compound LaNiO2, whose magnetic susceptibility exhibits non-Curie-Weiss behavior at low temperatures [3,4]. These examples may work as a blueprint for similar future studies of strongly correlated systems.

[1] Thomas Schäfer, Nils Wentzell, Fedor Šimkovic IV, Yuan-Yao He, Cornelia Hille, Marcel Klett, Christian J. Eckhardt, Behnam Arzhang, Viktor Harkov, François-Marie Le Régent, Alfred Kirsch, Yan Wang, Aaram J. Kim, Evgeny Kozik, Evgeny A. Stepanov, Anna Kauch, Sabine Andergassen, Philipp Hansmann, Daniel Rohe, Yuri M. Vilk, James P. F. LeBlanc, Shiwei Zhang, A.-M. S. Tremblay, Michel Ferrero, Olivier Parcollet, and Antoine Georges, Phys. Rev. X 11, 011058 (2021).
[2] Alexander Wietek, Riccardo Rossi, Fedor Šimkovic IV, Marcel Klett, Philipp Hansmann, Michel Ferrero, E. Miles Stoudenmire, Thomas Schäfer, and Antoine Georges, Phys. Rev. X 11, 041013 (2021).
[3] R. A. Ortiz, P. Puphal, M. Klett, F. Hotz, R. K. Kremer, H. Trepka, M. Hemmida, H.-A. Krug von Nidda, M. Isobe, R. Khasanov, H. Luetkens, P. Hansmann, B. Keimer, T. Schäfer, and M. Hepting, Phys. Rev. Res. 4, 023093 (2022).
[4] Marcel Klett, Philipp Hansmann, and Thomas Schäfer, Frontiers in Physics 10, 834682 (2022).