Boundary tension at the interface of helium films on an heterogeneous substrate

E. S. HERNÁNDEZ

Rostock

Conferencia; 17th International Conference on Recent Progress in Quantum Many Body Theories MBT17; 2013

Universidad de Rostock

This work focuses on the structure of the interfaces occurring at the edge of inhomogeneities on a chemically patterned surface, consisting of one or more different components. A typical example of such a material is a striped surface with alternating wettable and nonwettable adsorbers with respect to a given fluid. In such a case, the boundary tension is the interfacial energy cost that arises as a consequence of energy and entropy imbalance among the particles in the phases that meet at the boundary line. In this work I present  data on the structure and energetic of the interfacial profile between two half-films of liquid 4He on a chemically heterogeneous substrate consisting of two alkali metals, in a frame of a finite temperature-finite range density functional that permits detailed calculations of adsorption isotherms of helium on semiinfinite planar substrates. The results are analysed in terms of chemical potential at film coexistence, relative transverse spread of the half films and difference between adsorbing strenghts of the components. It is found that the highest energy cost is associated to the disappearance of layers occurring on the strongest adsorber.