Excitations and Correlations in One-Dimensional Heisenberg Antiferromagnetic Systems

Isao Harada, Yoshihiro Nishiyama, Yoshio Aoyama

Paul Louis Iske, W.J. Caspers

J. Lorenzana, R. Eder

We use numerical and analytical results to construct a simple ansatz for the energy dynamical correlation function of the one-dimensional antiferromagnetic Heisenberg model. This is applied to compute the phonon-assisted absorption spectra of magnetic excitations (spinons) in quasi-one-dimensional spin-1/2 insulators and shown to reproduce very well recent infrared measurements in ${\mathrm{Sr}}_{2}$ ${\mathrm{CuO}}_{3}$.

E. V. Orlenko, Fedor E. Orlenko, George G. Zegrya

We are interested in the anisotropic S=1 antiferromagnetic chain. System of particles with an arbitrary spin is described directly from the first principles, based on the symmetry law. The ground state of the one-dimensional S=1 pseudo-Heisenberg antiferromagnet with single-ion anisotropy is calculated. Excitations of the chain in the form of nonlinear spin waves and, in particular, the possibility of a soliton solution is considered.

András Sütö

Shu-Qing Bao, Hu Zhao, Jue-Lian Shen +1 more

The one-dimensional spin-1 Heisenberg antiferromagnetic chains are studied by a generalized two-time Green's-function method at finite temperature. 〈${\mathit{S}}_{\mathit{i}}^{\mathit{z}}$〉 is set to zero at each site to guarantee the lack of the long-range order in the one-dimensional Heisenberg system. The Green's functions are decoupled in terms of the correlation functions of spin operators. A set of self-consistent equations of the correlation functions are derived and solved numerically. Correlation functions of spin operators, thermodynamic properties such as the internal energy, and specific heat in the entire temperature region are obtained. The Haldane gap in the excitation spectrum appears naturally in the analytical result. When k is zero, there is a gap 2\ensuremath{\Delta}, which is 1.0J and close to the theoretical result of White and Huse. And there is a broad maximum in the temperature dependence of the specific heat. The properties of the thermodynamic quantities are consistent with the numerical results on the finite chains. \textcopyright{} 1996 The American Physical Society.