Theory of magnons in spin systems with Dzyaloshinskii-Moriya interaction
  We study in this paper magnetic properties of a system of quantum Heisenberg spins interacting with each other via a ferromagnetic exchange interaction J and an in-plane Dzyaloshinskii-Moriya interaction D. The non-collinear ground state due to the competition between J and D is determined. We employ a self-consistent Green'function theory to calculate the spin-wave spectrum and the layer magnetizations at finite T in two and three dimensions as well as in a thin film with surface effects. Analytical details and the validity of the method are shown and discussed. 
Sahbi El-Hog (LPTM), Hung T. Diep (LPTM), Henryk Puszkarski
cond-mat.stat-mech cond-mat.str-el