Soliton spin excitations in a Heisenberg helimagnet

We propose a new model for a helimagnet in analogy with the cholesteric liquid crystal and investigate its non-linear spin dynamics in the semi-classical limit. The study reveals that for specific parametric choices, the elementary spin excitations along the helical axis are governed by soliton modes. A multiple scale perturbation analysis on the more general non-integrable case shows that the helicity does not alter the velocity and amplitude of the soliton, but introduces some fluctuations in the localised region of the soliton.