Discrete magnetic breathers in monoaxial chiral helimagnet

I G Bostrem,E G Ekomasov,J Kishine,Vl E Sinitsyn,A S Ovchinnikov

doi:10.1063/9.0000045

Abstract

We analyze spatially localized breather excitations for the model of a discrete Heisenberg spin chain, which includes the antisymmetric exchange interaction and single-ion anisotropy of the easy-plane type. In a finite size chain the breather modes may be indexed by number of embedded kink-antikink pairs forming the regular breather lattice. The influence of the antisymmetric exchange on properties of the discrete breather modes is examined.

Highlights

According to generally accepted definition, a breather is a localized in space and periodic in time solution of either continuous media equations or discrete lattice equations
It was found out that nonlinearity and discreteness are two pivotal ingredients supporting these excitations, which were named as discrete breathers (DB) or intrinsic localized modes
A theoretical search for discrete breathers in spin systems was undertaken in Refs. 12–14, where possibility of their appearance has been demonstrated on the example of Heisenberg ferromagnetic and antiferromagnet spin chains with single-ion magnetic anisotropy

Summary

INTRODUCTION

According to generally accepted definition, a breather is a localized in space and periodic in time solution of either continuous media equations or discrete lattice equations. The discrete nonlinear lattices reveal spatially localized oscillating modes. A theoretical search for discrete breathers in spin systems was undertaken in Refs. 12–14, where possibility of their appearance has been demonstrated on the example of Heisenberg ferromagnetic and antiferromagnet spin chains with single-ion magnetic anisotropy. The localized breather modes have been studied in a weak ferromagnetic spin lattice with the Dzyaloshinskii–Moryia (DM) interaction.. Following the idea suggested in Ref. 12, we address the so-called phase of forced ferromagnetism, where in the ground state all spins align with an external magnetic field applied along the chiral axis.. II, we describe the model and basic equations to search for discrete breathers

THE MODEL

DISCRETE BREATHERS

ENERGY OF THE DISCRETE BREATHERS

CONCLUSIONS