Low-Temperature Specific Heats of Adsorbed Helium Monolayers in the Mobile Limit

Abstract
Jackson's model for adsorbed helium monolayers is suitable for studying thermodynamic properties in the mobile limit. In particular, low-temperature specific heats can be calculated over a range of areal densities. The dominant contributions come from longitudinal surface phonons. We report here (i) an extension of Jackson's model to account for surface-phonon—surface-phonon interactions, (ii) computations of low-temperature specific heats to several coverages, and (iii) a comparison of the computed results to experiment.