We investigate the critical behavior of the two-dimensional spin-1 Baxter-Wu model in a crystal field using entropic sampling simulations with the joint density of states. We obtain the temperature-crystal field phase diagram, which includes a tetracritical line ending at a pentacritical point. A finite-size scaling analysis of the maximum of the specific heat, while changing the crystal field anisotropy, is used to obtain a precise location of the pentacritical point. Our results give the critical temperature and crystal field as Tpc=0.98030(10) and Dpc=1.68288(62). We also detect that at the first-order region of the phase diagram, the specific heat exhibits a double peak structure as in the Schottky-like anomaly, which is associated with an order-disorder transition.
@article{arxiv.2008.13037,
title = {An entropic simulational study of the spin-$1$ Baxter-Wu model in a crystal field},
author = {L. N. Jorge and P. H. L. Martins and C. J. DaSilva and L. S. Ferreira and A. A. Caparica},
journal= {arXiv preprint arXiv:2008.13037},
year = {2021}
}