We compute the spin-wave dispersion of the square-lattice Heisenberg antiferromagnet at T=0 within the Dyson-Maleev formalism, to order 1/S. This allows us to calculate the spin-wave velocity renormalization factor, ${\mathit{Z}}_{\mathit{c}}$, to order O(1/${\mathit{S}}^2$). For the S=1/2 case, it is found that ${\mathit{Z}}_{\mathit{c}}$=1.1765±0.0002, in very good agreement with series-expansion estimates.

• Received 9 September 1991

DOI:https://doi.org/10.1103/PhysRevB.45.10131