Elementary excitations in one-dimensional spin-orbital models: neutral and charged solitons and their bound states

Abstract

We study, both numerically and variationally, the interplay between different types of elementary excitations in the model of a spin chain with anisotropic spin-orbit coupling, in the vicinity of the "dimer line" with an exactly known dimerized ground state. Our variational treatment is found to be in a qualitative agreement with the exact diagonalization results. Soliton pairs are shown to be the lowest excitations only in a very narrow region of the phase diagram near the dimer line, and the phase transitions are always governed by magnon-type excitations which can be viewed as soliton-antisoliton bound states. It is shown that when the anisotropy exceeds certain critical value, a new phase boundary appears. In the doped model on the dimer line, the exact elementary charge excitation is shown to be a hole bound to a soliton. Bound states of those "charged solitons" are studied; exact solutions for N-hole bound states are presented.

11 pages revtex, 6 figures

References in corpus (7)

• Phase diagram of a 1 dimensional spin-orbital model
• Numerical Study of the One-Dimensional Spin-Orbit Coupled System with SU(2)$\otimes$SU(2) Symmetry
• Effect of symmetry breaking perturbations in the one-dimensional SU(4) spin-orbital model
• Low-energy behavior of the spin-tube and spin-orbital models
• Effective Charge and Spin Hamiltonian for the Quarter-Filled Ladder Compound ${\alpha }^{\prime }$-NaV${}_2$O${}_5$
• Dynamical Properties of Spin-Orbital Chains in a Magnetic Field
• Effects of a magnetic field on the one-dimensional spin-orbital model

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