Scaling Theory of the Mechanical Properties of Amorphous Nano-Films

TL;DR

This paper develops a scaling theory for the mechanical properties of amorphous nano-films on crystalline substrates, using numerical simulations and Hessian matrix relations to analyze how substrate density and film thickness influence elasticity.

Contribution

It introduces a scaling framework that unifies the mechanical behavior of amorphous nano-films across various densities and thicknesses, highlighting substrate effects.

Findings

Substrate density significantly affects film elasticity.

Scaling laws enable data collapse across different parameters.

Substrate dominates the mechanical response of the system.

Abstract

Numerical Simulations are employed to create amorphous nano-films of a chosen thickness on a crystalline substrate which induces strain on the film. The films are grown by a vapor deposition technique which was recently developed to create very stable glassy films. Using the exact relations between the Hessian matrix and the shear and bulk moduli we explore the mechanical properties of the nano-films as a function of the density of the substrate and the film thickness. The existence of the substrate dominates the mechanical properties of the combined substrate-film system. Scaling concepts are then employed to achieve data collapse in a wide range of densities and film thicknesses.