Physical Review B
Thermodynamic properties of the fcc Ising antiferromagnet obtained from precision density of states calculations
A. D. Beath, Dominic H Ryan
Abstract
We calculate the density of states for the face-centered-cubic (fcc) Ising model with nearest-neighbor interactions using a Wang-Landau algorithm. This allows us to calculate thermodynamic quantities at all temperatures for both the ferromagnetic (FM) and antiferromagnetic (AF) models from the same data set, while avoiding the hysteresis usually occurring in models undergoing a first-order phase transition. For the FM model, our results are in agreement with high-temperature (HT) series expansion results, and are of the same precision. For the AF model which has a first-order transition, and where precise estimates of the critical behavior are lacking, we obtain ${T}_{N}=1.7217(8)$. We also obtain estimates of the free energy, internal energy, and entropy of both the ordered and disordered states at ${T}_{N}$ with a precision comparable to that obtained in the HT series for the FM model. Details of the finite-size scaling for the AF model are discussed, and a different convergence criterion for the Wang-Landau method is introduced.