Freezing of 4He and its liquid-solid interface from density functional theory -: art. no. 214522

We show that, at high densities, fully variational solutions of solidlike types can be obtained from a density functional formalism originally designed for liquid He-4. Motivated by this finding, we propose an extension of the method that accurately describes the solid phase and the freezing transition of liquid He-4 at zero temperature. The density profile of the interface between liquid and the (0001) surface of the He-4 crystal is also investigated, and its surface energy evaluated. The interfacial tension is found to be in semiquantitative agreement with experiments and with other microscopic calculations. This opens the possibility to use unbiased density functional (DF) methods to study highly nonhomogeneous systems, like He-4 interacting with strongly attractive impurities and/or substrates, or the nucleation of the solid phase in the metastable liquid.