DMFT+NRG study of orbital differentiation in three-orbital Hubbard models

The orbital-selective Mott phase (OSMP) in multi-orbital Hubbard models has been of high interest for a long time. While it has early been understood [1] that different bandwidths of the orbitals can lead to different critical interaction energies, the OSMP solely driven by crystal-field splitting (CFS) is more intricate. Here, we present a real-frequency dynamical mean-field theory and numerical renormalization group (DMFT+NRG) analysis of the OSMP driven by CFS in a three-orbital model and illustrate the singular Fermi-liquid properties of this phase [2]. On the example of Sr₂RuO₄, we show how our method can be used to study low-energy physics in a real-materials framework.

[1] V.I. Anisimov et al., EPJB 25, 191-201 (2002)
[2] M. Greger et al., arXiv:1312.0100 (2013)