Kondo dynamics in one-dimensional doped ferromagnetic insulators

TL;DR

This paper explores how doping a one-dimensional ferromagnetic insulator leads to Kondo-like effects due to magnon-holon interactions, revealing a crossover between different coupling regimes through numerical analysis.

Contribution

It introduces an effective field theory for magnon-holon interactions in doped 1D ferromagnetic insulators and identifies a Kondo effect arising from backscattering at the Fermi momentum.

Findings

Identification of a Kondo effect from magnon backscattering

Crossover between weak and strong coupling regimes

Numerical renormalization group analysis of the impurity model

Abstract

Some well-established examples of itinerant-electron ferromagnetism in one dimension occur in a Mott-insulating phase. We examine the consequences of doping a ferromagnetic insulator and cou- pling magnons to gapless charge fluctuations. Using a bosonization scheme for strongly interacting electrons, we derive an effective field theory for the magnon-holon interaction. When the magnon momentum matches the Fermi momentum of the holons, the backscattering of the magnon at low energies gives rise to a Kondo effect of a pseudospin defined from the chirality degree of freedom (right- or left-moving particles). The crossover between weak-coupling and strong-coupling fixed points of the effective mobile-impurity model is then investigated using a numerical renormalization group approach.