Coherence and metamagnetism in the two-dimensional Kondo lattice model

TL;DR

This study uses dynamical mean field theory to analyze the two-dimensional Kondo lattice model under magnetic fields, revealing a magnetization plateau linked to quasiparticle coherence and hybridization gap effects.

Contribution

It provides the first detailed DMFT analysis of the Kondo lattice model's spectral functions and magnetization behavior under magnetic fields, confirming theoretical predictions.

Findings

Identification of a zero-temperature magnetization plateau.

Spectral functions show rigid, hybridized bands with Zeeman shifts.

Plateau onset coincides with the chemical potential entering the hybridization gap.

Abstract

We report the results of dynamical mean field calculations for the metallic Kondo lattice model subject to an applied magnetic field. High-quality spectral functions reveal that the picture of rigid, hybridized bands, Zeeman-shifted in proportion to the field strength, is qualitatively correct. We find evidence of a zero-temperature magnetization plateau, whose onset coincides with the chemical potential entering the spin up hybridization gap. The plateau appears at the field scale predicted by (static) large-N mean field theory and has a magnetization value consistent with that of x=1-n_c spin-polarized heavy holes, where n_c < 1 is the conduction band filling of the noninteracting system. We argue that the emergence of the plateau at low temperature marks the onset of quasiparticle coherence.