Wetting Properties of Grain Boundaries in Solid Helium 4

Abstract

We have observed boundaries between hcp ${}^4$He crystal grains in equilibrium with liquid ${}^4$He. We have found that, when emerging at the liquid-solid interface, a grain boundary makes a groove whose dihedral angle $2\theta$ is non-zero. This measurement shows that grain boundaries are not completely wet by the liquid phase, in agreement with recent Monte Carlo simulations. Depending on the value of $\theta$, the contact line of a grain boundary with a solid wall may be wet by the liquid. In this case, the line is a thin channel with a curved triangular cross section, whose measured width agrees with predictions from a simple model. We discuss these measurements in the context of grain boundary premelting and for a future understanding of the possible supersolidity of solid ${}^4$He.

4 pages, 4 figures

References in corpus (3)

• Luttinger Liquid in the Core of Screw Dislocation in Helium-4
• Disorder and the Supersolid State of Solid ${}^4$He
• Nonclassical Rotational Inertia in Single Crystal Helium

Cited by in corpus (4)

• Observation of Unusual Mass Transport in Solid hcp 4He
• Solid 4He and the Supersolid Phase: from Theoretical Speculation to the Discovery of a New State of Matter? A Review of the Past and Present Status of Research
• Method for Computing Short-Range Forces between Solid-Liquid Interfaces Driving Grain Boundary Premelting
• Finite size Berezinski-Kosterlitz-Thouless transition at grain boundaries in solid ${}^4$He and role of ${}^3$He impurities