Heat capacity of fluid monolayers ofHe4

Abstract
The heat capacity of He4 adsorbed on graphite has been precisely measured over a fine grid of coverages for temperatures extending down to 100 mK and for coverages up to five atomic layers. The data indicate that the two-dimensional liquid is self-bound in each of the first three layers with an areal density of about 0.04 atom/Å 2. There is also evidence suggesting that this liquid undergoes a Kosterlitz-Thouless transition.