Highly Mobile Metastable State of He-4 Thin Films: A Glass Transition by Mechanical Perturbation?

Solid layers of helium on graphite surface are known to go into a highly mobile state (HMS) once the solid layer is enforced to slip on the substrate. The HMS collapses to the stable inert state with the lifetime extending over \(10^4\) s. In this paper, we suggest that the HMS is a structural glass by showing the similarities between the present system and an organic conductor named BEDT-TTF. The latter was recently discovered to be an electronic glass if the cooling rate is rapid enough across the freezing temperature (Wigner crystal formation temperature). We then address a novel annealing process promoted by a local condensate which should be seen for the present He-4 case as the condensation fraction grows in the liquid overlayer.