Model vapor-deposited glasses: growth front and composition effects

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Physical vapor deposition (PVD) is an experimental technique for creating stable glasses.
• These PVD-generated glasses exhibit properties akin to glasses aged for millennia.
• Previous molecular dynamics (MD) simulations explored PVD-inspired glass formation.

Purpose of the Study:

• To investigate the stability and formation mechanisms of binary glasses using a PVD-inspired MD approach.
• To assess the influence of composition on the properties of PVD-simulated glasses.
• To analyze the devitrification mechanism in thick, vapor-deposited glass films.

Main Methods:

• Molecular dynamics simulations of binary glass formation.
• Sequential particle addition to a growing film surface, mimicking PVD.
• Analysis of glass stability, composition, and devitrification dynamics.

Main Results:

• PVD-simulated glasses are more stable than those formed by gradual cooling.
• Glass composition significantly affects material properties, necessitating re-evaluation of thinner film simulations.
• A mobility front propagating from the free surface was identified as the devitrification mechanism.

Conclusions:

• PVD-inspired MD simulations provide a route to highly stable glasses.
• Compositional control is crucial for accurate property prediction in PVD glasses.
• Understanding the mobility front mechanism is key to preventing devitrification in vapor-deposited glasses.