Dynamical Correlation Functions of One-Dimensional Anisotropic Heisenberg Model with Spin 1/2. I : Ising-Like Antiferromagnets

概要

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Dynamics of one-dimensional Ising-like (strongly anisotropic) antiferromagnets is studied by the perturbation theory from the pure Ising limit and by an exact calculation for finite chains. Both calculations show that the des Cloizeaux-Gaudin (dC-G) "spin-wave" spectrum corresponds neither to a lower bound of excitation continuum nor to the peak position of the transverse response S_<xx>(Q,ω). A new interpretation is given of the spin-wave spectrum of CsCoCl_3 without relying on the dC-G theory. It is also shown that at elevated temperatures S_<xx>(Q,ω) has a three-peak structure. The longitudinal response S_<xx>(Q,ω) at low temperatures has a weak peak at the position of spin wave peak, while with increasing temperature S_<xx>(Q,ω) is dominated by the central peak due to thermally activated solitons, which was predicted by Villain.
理論物理学刊行会の論文
1980-03-25