Dynamics of the one-dimensional quantum antiferromagnet with Dzyaloshinski–Moriya interactions

Abstract The in-plane dynamical correlation function for the quantum one-dimensional antiferromagnet with a Dzyaloshinski–Moriya antisymmetric exchange term is calculated asymptotically exactly at low temperatures using a projection operator technique proposed by G. Reiter. The static correlation functions needed for the dynamics are evaluated using the harmonic approximation. Apart from a broadening of the spin-wave peak, the two-magnon processes give rise to additional resonances in the spectrum when the anisotropy parameter associated to the Dzyaloshinski–Moriya exchange is greater than the exchange constant.