Nonlinear Excitation in a Ferrimagnetic Zigzag Chain

We study the nonlinear excitation (solitons) in a ferrimagnetic polymer chain by using a total Hamiltonianconsisting of Su-Schrieffer-Heeger Hamiltonian and a Hubbard term. At half-rifling, the distortion of latticesforms domain wall solitons, while the spin configuration forms envelope solitons. The soliton pair is obtained ina range of the electron-electron (e-e) interaction U, which depends on the electron-phonon (e-ph) interaction.The spin solitons corresponding to the left domain wall and the right domain wall of the displacement are quitedifferent.