Low-temperature magnetic properties of the Kondo lattice model in one dimension

TL;DR

This study explores the low-temperature magnetic behaviors of the one-dimensional Kondo lattice model with classical spins, revealing new phases and challenging the validity of perturbative approaches at certain fillings.

Contribution

It identifies new chiral noncoplanar and collinear phases in the Kondo lattice model that are absent in the RKKY model, and shows the breakdown of perturbation theory at specific fillings.

Findings

Discovery of chiral noncoplanar phase.

Identification of collinear period-4 and 6 phases.

Persistence of period-4 collinear phase at weak coupling.

Abstract

Low-temperature magnetic properties of the one-dimensional Kondo-lattice model with classical localized spins are investigated by means of a Monte Carlo simulation combined with an exact diagonalization technique. Comparative simulations are also made for the RKKY classical Heisenberg model known to be perturbatively derived in the weak-coupling limit. In addition to the previously identified antiferromagnetic, ferromagnetic and coplanar helical phases, the chiral noncoplanar phase and the collinear phases of the period-4 and 6 are newly identified, neither of which is realized in the corresponding RKKY model. The period-4 collinear phase persists even in the weak-coupling limit at the 1/4- and 3/4-fillings, invalidating the perturbative approach at these fillings.