Bosonization Approach to the One-Dimensional Kondo Lattice Model at Half Filling: Reexamination

TL;DR

This paper reexamines the low-energy properties of the one-dimensional Kondo lattice model at half-filling using bosonization and renormalization group techniques, focusing on gap formation and phase transitions.

Contribution

It provides a detailed analysis of spin and charge gap formation and the impact of electron interactions on phase behavior in the Kondo lattice model.

Findings

Repulsive interactions alter the gap dependence on Kondo coupling.

Attractive interactions can induce a transition to a metallic phase.

Both antiferromagnetic and ferromagnetic couplings are considered.

Abstract

Low-energy properties of the one-dimensional Kondo lattice model are investigated by using bosonization and renormalization group methods. The formation of the spin and charge excitation gaps at half-filling is discussed in detail both for antiferromagnetic and ferromagnetic Kondo couplings. Also, the effect of the interaction between conduction electrons on the gap formation is studied both for the Kondo insulating phase and for the Haldane gap phase. It is found that while the repulsive interaction changes the dependence of the excitation gap on the Kondo exchange coupling, the attractive interaction can drive the Kondo (or Haldane) insulating phase to a completely different phase of massless metallic states.