Spin-wave modes in a compressible Heisenberg chain of classical spins

The spin dynamics of a compressible chain of classical spins is studied by means of a four pole approximation for the spin relaxation function. The frequency moments are calculated with the help of a computer. The general qualitative influence of the coupling to the phonons on the dynamic structure factor is discussed. Quantitative results for frequency shift, line width and the condition for the observability of spin waves are obtained. Especially the latter is quite different from the result for the rigid Heisenberg chain. The coupling to the phonon degrees of freedom does not lead to additional resonances in the spin spectrum.Aspirant van het Belgisch Nationaal Fonds voor Wetenschappelijk Onderzoek