Dynamical Correlation Functions of OneDimensional Anisotropic Heisenberg Model with Spin 1/2. I IsingLike Antiferromagnets
Abstract
Dynamics of onedimensional Isinglike (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 CloizeauxGaudin (dCG) ``spinwave'' 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 spinwave spectrum of CsCoCl_{3} without relying on the dCG theory. It is also shown that at elevated temperatures S_{xx}(Q, ω) has a threepeak 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.
 Publication:

Progress of Theoretical Physics
 Pub Date:
 March 1980
 DOI:
 10.1143/PTP.63.743
 Bibcode:
 1980PThPh..63..743I