Roughening transition in the interface between superfluid and solidHe4

Abstract

The equilibrium shape and dimensions of a small crystal are presented by consideration of its anisotropic surface tension and gravitational effects. The roughening transition is discussed phenomenologically in terms of the facet stabilizing cusp points appearing in the surface tension. This is applied to recent experiments on the interface between superfluid and solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$.