Date of Original Version
Direct Monte Carlo sampling is employed to obtain estimates of excess surface free energies of three-dimensional XY models at criticality. Results for simple-cubic and body-centered-cubic lattices are consistent with universality of finite-size scaling amplitudes. The results are used to estimate the magnitude of the thinning effect, mediated by the incipient long-ranged correlations, on liquid-helium films at the λ point.
K. K. Mon and M. P. Nightingale. (1987). "Critical surface free energies and universal finite-size scaling amplitudes of three-dimensional XY models by direct Monte Carlo sampling." Physical Review B, 35, 3560. Available at: http://dx.doi.org/10.1103/PhysRevB.35.3560