Competition of striped magnetic order and partial Kondo screened state in the Kondo lattice model

TL;DR

This study investigates the competition between magnetic orders and the partial Kondo screened state in the Kondo lattice model on a square lattice, revealing the conditions under which each state is stable and their spectral properties.

Contribution

It introduces a detailed analysis of magnetic phases near quarter filling in the Kondo lattice model using dynamical mean field theory, highlighting the stability of the PKS state.

Findings

PKS state is insulating with a flat band above the Fermi energy.

Striped magnetic state is metallic and stable at weak coupling.

PKS state becomes stable at intermediate coupling due to larger Kondo energy gain.

Abstract

We analyze the magnetically ordered phases in the Kondo lattice model on a square lattice around quarter filling using the dynamical mean field theory. We find that close to quarter filling besides the paramagnetic phase, at least three magnetic phases compete. These phases are a ferromagnetic state, a partial Kondo screened state, which is a combination of charge order and magnetic order, and a striped magnetic phase, which is ferromagnetically ordered in one direction and antiferromagnetically in the other direction. We analyze the spectral properties of these states and show that the PKS state is insulating with a flat band above the Fermi energy, while the other states are metallic. Furthermore, we demonstrate that the energy gain by the Kondo effect is larger in the PKS state, while the striped magnetic state can gain more energy from the RKKY interaction. Thus, while the striped magnetic state is stable at weak coupling, the PKS state becomes stable at intermediate coupling.