Two-dimensional XXZ model on a square lattice: a Monte Carlo simulation

Results of Monte Carlo simulations of the ferromagnetic classical XXZ model on a square lattice are reported for interactions of the out of plane spin components lambda varying between 0 and 0.99. For all the values of lambda the signature of a Berezinskii-Kosterlitz-Thouless (BKT) phase transition was observed, and the corresponding critical temperature was located both by BKT fits and finite-size scaling methods. Data for in-plane and out of plane susceptibility, correlation length, specific heat, and internal energy are given in abroad range of temperature and for lattice sizes ranging from 32 x 32 to 256 x 256.