Dimerization and Solitons in One-Dimensional XY-Z Antiferromagnets

Abstract

Our previous calculations of the lattice distortion and the formation energy of a soliton in the one-dimensional antiferromagnetic Heisenberg spin-Peierls systems are refined and extended to the case of XY-Z model. The spin degree of freedom are represented by the phase Hamiltonian with the help of boson representation of fermions introduced by the Jordan-Wigner transformation. Parameters in this phase Hamiltonian are adjusted so that spin wave velocity and exponent of correlation function agree with exact results. This adjustment is shown to give also exact spin susceptibility in the absence of lattice distortion. Based on this phase Hamiltonian of the XY-Z the model localized excitations (solitons) in presence of lattice distortions are the examined in details including the width, formation energy and the magnetic field dependence. © 1981, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.