Within Dyson-Maleev (DM) transformation and self-consistent mean-field treatment, the N\'eel order/disorder transition is studied for an antiferromagnetic Heisenberg model which is defined on a square lattice with a nearest neighbour exchange J1 and a next-nearest neighbour exchange J2 along only one of the diagonals. It is found that the N\'eel order may exist up to J2/J1=0.572, beyond its classically stable regime. This result qualitatively improves that from linear spin-wave theory based on Holstein-Primakoff transformation.
@article{arxiv.cond-mat/0101145,
title = {The N\'eel order for a frustrated antiferromagnetic Heisenberg model: beyond linear spin-wave theory},
author = {Qingshan Yuan},
journal= {arXiv preprint arXiv:cond-mat/0101145},
year = {2009}
}