Chirality tunneling and quantum dynamics for domain walls in mesoscopic ferromagnets

TL;DR

This paper investigates the quantum tunneling and dynamics of ferromagnetic domain walls in one-dimensional spin chains, revealing spin-dependent effects and potential observability in mesoscopic magnetic structures.

Contribution

It demonstrates that tunneling probability is independent of domain wall size and explores the interplay between position and chirality tunneling, highlighting differences between integer and half-integer spins.

Findings

Tunneling probability remains large regardless of domain wall size.

Strong interplay between domain wall position and chirality tunneling.

Distinct dispersion laws for integer versus half-integer spin chains.

Abstract

We studied the quantum dynamics of ferromagnetic domain walls (topological kink-type solitons) in one dimensional ferromagnetic spin chains. We show that the tunneling probability does not depend on the number of spins in a domain wall; thus, this probability can be large even for a domain wall containing a large number of spins. We also predict that there is a strong interplay between the tunneling of a wall from one lattice site to another (tunneling of the kink coordinate) and the tunneling of the kink topological charge (so-called chirality). Both of these elementary processes are suppressed for kinks in one-dimensional ferromagnets with half-integer spin. The dispersion law (i.e., the domain wall energy versus momentum) is essentially different for chains with either integer or half-integer spins. The predicted quantum effects could be observed for mesoscopic magnetic structures, e.g., chains of magnetic clusters, large-spin molecules, or nanosize magnetic dots.