Kondo insulators in the periodic Anderson model: a local moment approach

TL;DR

This paper develops a non-perturbative local moment approach within dynamical mean-field theory to accurately describe the single-particle dynamics of Kondo insulators in the periodic Anderson model across all energy scales.

Contribution

It introduces a comprehensive, energy-scale encompassing method that captures both strong and weak coupling regimes, emphasizing strong coupling dynamics and spectral scaling.

Findings

Successfully describes strong coupling behavior and exponential quasiparticle scales.

Reproduces Fermi liquid low-energy properties.

Provides a unified framework for all interaction strengths.

Abstract

The symmetric periodic Anderson model is well known to capture the essential physics of Kondo insulator materials. Within the framework of dynamical mean-field theory, we develop a local moment approach to its single-particle dynamics in the paramagnetic phase. The approach is intrinsically non-perturbative, encompasses all energy scales and interaction strengths, and satisfies the low-energy dictates of Fermi liquid theory. It captures in particular the strong coupling behaviour and exponentially small quasiparticle scales characteristic of the Kondo lattice regime, as well as simple perturbative behaviour in weak coupling. Particular emphasis is naturally given to strong coupling dynamics, where the resultant clean separation of energy scales enables the scaling behaviour of single-particle spectra to be obtained.