Phase Diagram of the 1D Kondo Lattice Model

TL;DR

This paper uses a new infinite size DMRG method to precisely map the phase boundary between paramagnetic and ferromagnetic states in the 1D Kondo lattice model, resolving previous controversies.

Contribution

It introduces a novel DMRG approach that conserves total spin, enabling accurate determination of phase boundaries in the 1D Kondo lattice model.

Findings

The ferromagnetic boundary is below J ≈ 3.5 across all band fillings.

The method resolves previous debates about the ferromagnetic region near half filling.

The phase diagram is clarified with high precision.

Abstract

We determine the boundary of the fully polarized ferromagnetic ground state in the one dimensional Kondo lattice model at partial conduction electron band filling by using a newly developed infinite size DMRG method which conserves the total spin quantum number. The obtained paramagnetic to ferromagnetic phase boundary is below $J \approx 3.5$ for the whole range of band filling. By this we solve the controversy in the phase diagram over the extent of the ferromagnetic region close to half filling.