Re-examination of the 2D spin-1 Blume-Capel model

Dong-Hee Kim

In this talk, we present the Wang-Landau (WL) method and its application to characterizing the tricriticality of the two-dimensional spin-1 Blume-Capel model. The joint density of states is measured for systems with sizes up to 48x48 sites, which allows an accurate identification of the first-order transitions and tricritical scaling behavior. First, at a large crystal field, we find out a double-peak structure of the specific heat where the previously unveiled Schottky-like anomaly appears together with the first-order transition peak. Second, we systematically determine the first-order transition curve which provides a significant improvement from the implicit line of the few previous data points. Finally, we characterize the tricritical exponents through finite-size-scaling analysis within the fully WL framework. The excellent data-curve collapses in the finite-size scaling accurately determine the three tricritical eigenvalue exponents, providing the first WL verification of the conjectured exact values of the tricritical exponents in two dimensions.