THERMODYNAMICS OF BOSON LIQUID-FILMS

Theoretical studies of films of liquid He-4 adsorbed to strong, plane substrates indicate that the growth of such films occurs through a seq uence of first-order phase transitions - ''layering transitions'' - wh ich are a direct consequence of the short-range, hard-core like intera ction between individual helium atoms. The present work examines the e ffects of temperature on these transitions. At given temperatures, the spinodal points and phase coexistence boundaries are determined for t he transitions. Increasing the temperature tends to decrease the cover age spall of the transition regions, signalling the possible existence of a critical point terminating the two-phase equilibrium.