Nonlinear spin-wave theory for the quasi-two-dimensional antiferromagnetic Heisenberg model.

Abstract

The quasi-two-dimensional antiferromagnetic Heisenberg model is used to describe the magnetic properties of ${\mathrm{La}}_{2}$${\mathrm{CuO}}_{4}$. In this model, the in-plane interaction is J and interplane coupling is J'. Studied with nonlinear spin-wave theory the Heisenberg model gives a connection between the ground-state energy and the parameter \ensuremath{\lambda}=J'/J, the N\'eel temperatures, and the softening temperatures for different \ensuremath{\lambda}. At \ensuremath{\lambda}=0 and \ensuremath{\lambda}=1, these results are in satisfactory agreement with the results of other theories of two- and three-dimensional antiferromagnetic Heisenberg models, respectively.