Uncovering non-Fermi-liquid behavior in Hund metals: critical behavior of a three-orbital Kondo model

When using dynamical mean field theory (DMFT) to study Hund metals, one arrives at self-consistent impurity models in which bath and impurity both have spin and orbital degrees of freedom. If these are screened at different energy scales, T_K^sp < T_K^orb, the intermediate energy window is governed by a novel non-Fermi-liquid (NFL) fixed point, involving screened orbital degrees of freedom weakly coupled to an unscreened local spin. Here we characterize the corresponding NFL behavior in detail for a 3-orbital Kondo model, tuned such that the NFL energy window is very wide. We find excellent agreement between conformal field theory (CFT) predictions and numerical renormalization group (NRG) results.