Kosterlitz-Thouless transition for 4He films adsorbed to rough surfaces -: art. no. 086106

We report the study of adsorption isotherms of He-4 on several well characterized rough CaF2 surfaces using a quartz crystal microbalance technique at 1.672 K. The signature of decoupled mass observed on crossing the Kosterlitz-Thouless transition as a function of He-4 film thickness decreases and becomes increasingly difficult to identify as the surface roughness is increased. A peak in the dissipation, indicative of the onset of superfluidity, changes little with roughness.