Renormalized parameters and perturbation theory for an n-channel Anderson model with Hund's rule coupling: Asymmetric case

TL;DR

This paper applies renormalized perturbation theory and NRG calculations to analyze the low-energy properties of an n-channel Anderson model with Hund's coupling, revealing detailed susceptibilities and Kondo behaviors.

Contribution

It provides a comprehensive analysis of the asymmetric n-channel Anderson model with Hund's rule coupling using renormalized parameters derived from NRG calculations.

Findings

Charge susceptibility is suppressed in the strong correlation regime.

Different Kondo behaviors are observed at nd=1 and nd=2.

The study offers detailed plots of susceptibilities and Wilson ratios.

Abstract

We explore the predictions of the renormalized perturbation theory for an 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 occupation at the impurity site, nd. From these we deduce the spin, orbital 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 nd=1 and nd=2. One unexpected feature of the results is the suppression of the charge susceptibility in the strong correlation regime over the occupation number range 1 <nd <3.