Anderson impurity in a correlated conduction band

TL;DR

This paper explores how a magnetic impurity behaves in a correlated metallic host, revealing new spectral features and an enhanced Kondo scale, with implications for experimental observation.

Contribution

It combines dynamical mean-field theory and numerical renormalization group to analyze impurity physics in a Hubbard band, uncovering novel spectral features and correlation effects.

Findings

Discovery of new spectral side peaks

Enhanced Kondo scale due to correlations

Kondo scale vanishes exponentially at small hybridization

Abstract

We investigate the physics of a magnetic impurity with spin 1/2 in a correlated metallic host. Describing the band by a Hubbard Hamiltonian, the problem is analyzed using dynamical mean-field-theory in combination with Wilson's nonperturbative numerical renormalization group. We present results for the single-particle density of states and the dynamical spin susceptibility at zero temperature. New spectral features (side peaks) are found which should be observable experimentally. In addition, we find a general enhancement of the Kondo scale due to correlations. Nevertheless, in the metallic phase, the Kondo scale always vanishes exponentially in the limit of small hybridization.