Renormalized parameters and perturbation theory for ann-channel Anderson model with Hund’s rule coupling: Asymmetric case

Abstract

We explore the predictions of the renormalized perturbation theory for the $n$-channel Anderson model, both with and without Hund's rule coupling, in the regime away from particle-hole symmetry. For the model with $n=2$ we deduce the renormalized parameters from numerical renormalization-group calculations and plot them as a function of the local occupation of the impurity site ${n}_{d}$. From the exact relations in terms of the renormalized parameters, we calculate the orbital, spin and charge susceptibilities, Wilson ratios, and quasiparticle density of states at $T=0$, in the different parameter regimes, which gives a comprehensive overview of the low-energy behavior of the model. We compare the difference in Kondo behaviors at the points, where ${n}_{d}=1$ and ${n}_{d}=2$. Some unexpected features of the results are that a strong on-site interaction gives significant renormalization and suppression charge susceptibility in the intermediate valence regimes, and the peaks in the spin susceptibility away from the particle-hole symmetric case do not occur at integer values ${n}_{d}=1,3$