Dynamical effects of phonons on soliton binding in spin-Peierls systems

TL;DR

This paper investigates how dynamical phonons influence soliton interactions in spin-Peierls systems, revealing a transition to dimerization and the conditions for soliton binding through numerical and analytical methods.

Contribution

It demonstrates that dynamical magneto-elastic coupling induces a dimerized phase and explores the conditions under which solitons bind or remain unbound in spin-Peierls chains.

Findings

Transition to dimerized state due to phonon coupling

No soliton binding in isolated chains

Interchain coupling can produce bound states

Abstract

The role of dynamical magneto-elastic coupling in spin-Peierls chains is investigated by numerical and analytical techniques. We show that a Heisenberg spin chain coupled to dynamical optical phonons exhibits a transition towards a spontaneously dimerized state in a wide range of parameter space. The low energy excitations are characterized as solitons. No binding between solitons occurs in the isolated spin-phonon chain and the dynamical spin structure factor shows a broad magnon dispersion. However, elastic interchain coupling can lead to the formation of bound states.