Structural Signatures of Ultrastability in a Deposited Glassformer

Glasses obtained from vapor deposition on a cold substrate have superior thermodynamic and kinetic stability with respect to ordinary glasses. Here we perform molecular dynamics simulations of vapor deposition of a model glassformer and investigate the origin of its high stability compared to that of ordinary glasses. We find that the vapor deposited glass is characterized by locally favored structures (LFSs) whose occurrence correlates with its stability, reaching a maximum at the optimal deposition temperature. The formation of LFSs is enhanced near the free surface, hence supporting the idea that the stability of vapor deposited glasses is connected to the relaxation dynamics at the surface.

Automated summary

Glasses obtained from vapor deposition on a cold substrate have superior thermodynamic and kinetic stability compared to ordinary glasses due to the presence of locally favored structures (LFSs) that enhance stability near the free surface. Molecular dynamics simulations reveal that the occurrence of LFSs correlates with the stability of vapor deposited glasses, reaching a maximum at the optimal deposition temperature.