QUANTUM RENORMALIZATIONS IN THE SPIN-1 HEISENBERG-ANTIFERROMAGNET ON THE SQUARE LATTICE

The renormalized parameters, characterizing the static and dynamic low-temperature properties of the spin-1 Heisenberg antiferromagnet on the square lattice, are estimated by expansions around the Ising limit. The calculations include the renormalization of the perpendicular susceptibility () and the frequency moments of the inelastic light scattering spectra from spin-pair excitations. The results are used to assess the quantitative accuracy of the spin-wave calculations of Oguchi for and the two-magnon calculation of Parkinson for the light scattering spectra. They are found to be in agreement with experiments on K2NiF4. © 1990 The American Physical Society.