Dresden 2020 – wissenschaftliches Programm
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TT 47.21: Poster
Mittwoch, 18. März 2020, 15:00–19:00, P2/3OG
Orbital differentiation in Hund metals — •Fabian B. Kugler1, Seung-Sup B. Lee1, Manuel Zingl2, Hugo U. R. Strand2, Andreas Weichselbaum3, Gabriel Kotliar4, Antoine Georges2, and Jan von Delft1 — 1Ludwig-Maximilians-Universität München, Germany — 2Flatiron Institute - Simons Foundation, USA — 3Brookhaven National Laboratory, USA — 4Rutgers University, USA
Orbital differentiation is a common theme in multi-orbital systems, yet a complete understanding of it is still missing. Here, we focus on three-orbital Hubbard models to describe the t2g bands of materials such as ruthenates and iron-based superconductors, and provide results of unprecedented accuracy by using the numerical renormalization group as real-frequency impurity solver for dynamical mean-field theory. First, we consider a minimal model for orbital differentiation, where a crystal field shifts one orbital in energy, and describe the various phases with dynamic correlation functions. Upon approaching the orbital-selective Mott transition, we find a strongly suppressed spin-coherence scale and uncover the emergence of a singular Fermi liquid and interband doublon-holon excitations. Then, we apply our method to the paradigmatic material Sr2RuO4 in a real-materials framework. We illustrate distinctive Hund-metal features and provide theoretical evidence for a Fermi-liquid scale of about 25 Kelvin.