Localized spin excitations in a nonlinear antiferromagnetic spin lattice with higher order interactions

Abstract

The dynamical theory of soliton excitation in a one-dimensional antiferro- magnet is examined using a modified Hamiltonian that considers not only the bilinear and D-M interactions but also the biquadratic anisotropic inter- action. Derivation of the two coupled nonlinear partial differential equations that governs the system’s dynamics involves the introduction of the Holstein- Primakoff transformation, the coherent state ansatz and the time dependent variational principle. Utilizing the Sine-Cosine function method the soliton excitation and the impact of interaction parameters on the system are exam- ined.