Orbital differentiation in Hund metals
Abstract
Orbital differentiation is a common theme in multiorbital systems, yet a complete understanding of it is still missing. Here, we consider a minimal model for orbital differentiation in Hund metals with a highly accurate method: We use the numerical renormalization group as a real-frequency impurity solver for a dynamical mean-field study of three-orbital Hubbard models, where a crystal field shifts one orbital in energy. The individual phases are characterized with dynamic correlation functions and their relation to diverse Kondo temperatures. 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. Our theory describes the diverse polarization-driven phenomena in the bands of materials such as ruthenates and iron-based superconductors, and our methodological advances pave the way towards real-frequency analyses of strongly correlated materials.
Cite
@article{arxiv.1904.10774,
title = {Orbital differentiation in Hund metals},
author = {Fabian B. Kugler and Seung-Sup B. Lee and Andreas Weichselbaum and Gabriel Kotliar and Jan von Delft},
journal= {arXiv preprint arXiv:1904.10774},
year = {2020}
}