Surface-Mediated Formation of Stable Glasses

Abstract

Surfaces mediate the formation of stable glasses (SGs) upon physical vapor deposition (PVD) for a wide range of glass formers. The thermodynamic and kinetic stability of SGs and their anisotropic packing structures are controlled through the deposition parameters (deposition temperature and rate) as well as the chemical structure and composition of the glass former. The resulting PVD glass properties can therefore be related to the structure and dynamics of the glass surface, which can have oriented packing, enhanced surface diffusion, and a lower glass transition temperature, and can facilitate an enhanced aging rate of the interfacial region. We review our current understanding of the details of this surface-mediated SG formation process and discuss key gaps in our knowledge of glass surface dynamics and their effect on this process.