Self-consistent interaction of magnons in a frustrated quantum antiferromagnet

(Received 19 December 1991, accepted 27 January 1992)

Abstract
We study the magnon interactions by means of a self-consistent calculation in a frustrated quantum Heisenberg antiferromagnet with first and second neighbor exchange couplings. We have used the Hartree-Fock-Bogolyubov scheme at zero temperature. The effect of frustration on the shape of the spin-wave spectrum is investigated: we find a strong decrease of the spin-wave velocity. A clear deviation from spin wave theory is found when comparing with finite lattice results.