PATH-INTEGRAL MONTE-CARLO SIMULATIONS OF THIN HE-4 FILMS ON A H-2 SURFACE

Atomatically thin He-4 films of up to three monolayers on molecular hydrogen (1, 1, 1) surfaces are studied at T = 0.5 K, using path integral Monte Carlo. We compute the binding energy of He-4 to the H-2 substrate as a function of He-4 coverage and obtain evidence of the prewetting transition. Density profiles perpendicular to the He-4-H-2 interface are obtained, as well as the zero point motion and effective mass of He-4 parallel to the substrate surface. The superfluid density of He-4 vs. coverage is calculated, and the intermediate scattering function is computed, from which we estimate the speed of third sound Finally, we calculate the vorticity-vorticity correlation function.