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, an additional 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.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, an additional 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.

arXiv:cond-mat/0008321Physical review. B, Condensed matterJan 22, 200120 citations

Solitons in Quantum Spin Chains

H.-J. Mikeska, Seiji Miyashita, Gerald H. Ristow

NATO ASI series. Series B : PhysicsJan 1, 19911 citation

Quasi-soliton scattering in quantum spin chains

Davide Fioretto, Rogier Vljim, Martin Ganahl +4 more

Bulletin of the American Physical SocietyMar 18, 20160 citations

Soliton bound states in the Raman spectrum of pure and doped spin-Peierls chains

David Augier, Erik Schwartz Sørensen, José A. Riera +1 more

We investigate the occurrence of singlet bound states in the Raman spectrum of dimerized spin 1/2 chains by exact diagonalization and density matrix renormalization-group techniques. We predict that several bulk $\ensuremath{\delta}$ peaks could be observed in pure systems. Furthermore, we show that additional low-energy lines arise from nonmagnetic impurity doping. These features are interpreted in terms of soliton-antisoliton and soliton-impurity bound states, respectively. Energies and spectral weights associated with these bound states are sensitive to lattice relaxation effects. Our results are discussed in the context of the inorganic spin-Peierls compound ${\mathrm{CuGeO}}_{3}$ and quantitatively compared to recent Raman experiments.We investigate the occurrence of singlet bound states in the Raman spectrum of dimerized spin 1/2 chains by exact diagonalization and density matrix renormalization-group techniques. We predict that several bulk $\ensuremath{\delta}$ peaks could be observed in pure systems. Furthermore, we show that additional low-energy lines arise from nonmagnetic impurity doping. These features are interpreted in terms of soliton-antisoliton and soliton-impurity bound states, respectively. Energies and spectral weights associated with these bound states are sensitive to lattice relaxation effects. Our results are discussed in the context of the inorganic spin-Peierls compound ${\mathrm{CuGeO}}_{3}$ and quantitatively compared to recent Raman experiments.

arXiv:cond-mat/9812174Physical review. B, Condensed matterJul 1, 199927 citations

Dynamical effects of phonons on soliton binding in quasi-one-dimensional spin–Peierls systems

David Augier, Didier Poilblanc, Erik Schwartz Sørensen +1 more

Abstract The role of dynamical magneto-elastic coupling in spin–Peierls chains is investigated by various numerical techniques. We show that, generically, a Heisenberg spin chain coupled to dynamical optical phonons exhibits a transition towards a spontaneously dimerized state. The low energy excitations are characterized as topological solitons. No binding between solitons occurs in the isolated spin–phonon chain. However, elastic interchain coupling can lead to the formation of bound states.Abstract The role of dynamical magneto-elastic coupling in spin–Peierls chains is investigated by various numerical techniques. We show that, generically, a Heisenberg spin chain coupled to dynamical optical phonons exhibits a transition towards a spontaneously dimerized state. The low energy excitations are characterized as topological solitons. No binding between solitons occurs in the isolated spin–phonon chain. However, elastic interchain coupling can lead to the formation of bound states.

APSMar 1, 19980 citations

Soliton-Bound States in the Magnetic Gap

Alan H. Luther

Springer series in solid-state sciencesJan 1, 19781 citation

{\mathrm{CuGeO}}_{3}

and quantitatively compared to recent Raman experiments.