The Néel order for a frustrated antiferromagnetic Heisenberg model: beyond linear spin-wave theory
arXiv:cond-mat/0101145 · doi:10.1016/S0375-9601(00)00625-3
Abstract
Within Dyson-Maleev (DM) transformation and self-consistent mean-field treatment, the Néel order/disorder transition is studied for an antiferromagnetic Heisenberg model which is defined on a square lattice with a nearest neighbour exchange $J_1$ and a next-nearest neighbour exchange $J_2$ along only one of the diagonals. It is found that the Néel order may exist up to $J_2/J_1=0.572$, beyond its classically stable regime. This result qualitatively improves that from linear spin-wave theory based on Holstein-Primakoff transformation.
10 pages, 4 eps figures