Nonlinear Excitation in a Ferrimagnetic Zigzag Chain

We study the nonlinear excitation (solitons) in a ferrimagnetic polymer chain by using a total Hamiltonian consisting of Su-Schrieffer-Heeger Hamiltonian and a Hubbard term. At half-filling, the distortion of lattices forms domain wall solitons while the spin configuration forms the envelope solitons. The soliton pair is obtained in a 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 quite different.