Superfluidity of monolayer helium films

We report the first theoretical results indicating the presence of monolayer superfluidity in He-4 films on a single crystal Li surface, Path integral Monte Carlo simulations results show that He-4 adsorbs strongly on Li, where it forms a superfluid liquid monolayer. On K, instead, the film is spread in surface-normal direction, and localized laterally. We discuss the implication of these results for wetting and superfluid transitions.