Dimerization induced by the RKKY interaction

TL;DR

This paper discovers a new spin dimerization phase in a one-dimensional Kondo lattice model at quarter filling, driven by RKKY interactions, and links it to experimental spin-Peierls phases in organic compounds.

Contribution

It provides the first example of dimerization induced indirectly by itinerant electrons in the Kondo lattice model.

Findings

Identifies spin dimerization at quarter filling in the Kondo lattice.

Links dimerization to RKKY interaction form.

Suggests a richer phase diagram for heavy fermion physics.

Abstract

We report the presence of spin dimerization in the ground state of the one dimensional Kondo lattice model at quarter filling. The emergence of this new phase of the Kondo lattice can be traced to the form of the RKKY interaction between the localized moments and provides the first example of dimerization induced indirectly by itinerant electrons. We propose this dimer ordering as the driving mechanism of the spin-Peierls phase observed in the quasi-one-dimensional organic compounds (Per)$_{2}$M(mnt)$_{2}$ (M=Pt, Pd). Moreover, this suggests that a richer phase diagram than the Doniach paradigm may be needed to accommodate the physics of heavy fermion materials.