SPIN EXCITATIONS IN AN ANISOTROPIC J_1–J_2 HEISENBERG MODEL

摘要

We investigate the spin-wave excitation spectrum in an antiferromagnet for the anisotropic J_1–J_2 and isotropic quasi-two-dimensional Heisenberg models with an arbitrary spin S. We consider the random phase approximation (Tyablikov decoupling) and the linear spin-wave approximation. We calculate the temperature dependence of the magnetization and the Néel temperature and compare it with experimental results for high-temperature cuprate superconductors and iron-based compounds.