Heavy electrons from Hund's rule and short-range Antiferromagnetism

TL;DR

This paper explores how short-range antiferromagnetism and Hund's rule coupling in a one-dimensional ferromagnetic Kondo lattice lead to the emergence of heavy electron states, highlighting the interplay of magnetic interactions and electron coherence.

Contribution

It introduces a solvable model demonstrating how antiferromagnetic correlations induce heavy electron behavior in a ferromagnetic Kondo lattice.

Findings

Short-range antiferromagnetism causes triplet states to become heavy singlets.

Heavy electron ground state emerges due to magnetic interactions.

Triplet propagation is significantly affected by antiferromagnetic correlations.

Abstract

We investigate the one-dimensional ferromagnetic Kondo lattice in the hole-rich region. Of interest to us is the intermediate situation where the ferromagnetic Kondo coupling (Hund's coupling) is comparable to the electron bandwidth. The forced alignment favors triplet states whereas singlet states enter in a quite low-density regime. The direct antiferromagnetic exchange between the core spins is assumed to still prevail over the double exchange. We discuss a solvable limit showing that short-range antiferromagnetism in the spin array will affect the coherent propagation of triplets, i.e., turns a light triplet onto a heavy singlet, resulting in a heavy electron ground state.