2-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 v alues of lambda the signature of a Berezinskii-Kosterlitz-Thouless (BK T) phase transition was observed, and the corresponding critical tempe rature was located both by BKT fits and finite-size scaling methods. D ata for in-plane and out of plane susceptibility, correlation length, specific heat, and internal energy are given in abroad range of temper ature and for lattice sizes ranging from 32 x 32 to 256 x 256.