The phase diagram of the baxter-Wu model in the magnetic field and temperature plane

Abstract

Abstract Using the Fisher zeros of the partition function of a finite sized cluster with ‘spherical’ boundary conditions an approximate phase diagram in the magnetic field—temperature plane is obtained for the Baxter-Wu model. The phase diagram compares favourably with previous approximations as well as the known exact results when the magnetic field is zero. The accuracy of the approximated phase diagram, especially for small values of the magnetic field, is dependent on the fact, as shown previously, that for zero magnetic field the Fisher zeros for this cluster lie on loci giving the exact zero field critical temperature.