Elasticity in crystals with high density of local defects : insights from ultra-soft colloids

TL;DR

This paper develops a first-principles theoretical framework to understand how high densities of point defects affect the elasticity of crystals, validated through molecular dynamics simulations.

Contribution

It introduces a microscopic approach to incorporate defect dynamics into elasticity theory for complex crystals near melting.

Findings

Defects significantly alter elastic properties.

Theoretical predictions match simulation results.

Insights into defect-driven mechanical behavior.

Abstract

In complex crystals close to melting or at finite temperatures, different types of defects are ubiquitous and their role becomes relevant in the mechanical response of these solids. Conventional elasticity theory fails to provide a microscopic basis to include and account for the motion of point-defects in an otherwise ordered crystalline structure. We study the elastic properties of a point-defect rich crystal within a first-principles theoretical framework derived from microscopic equations of motion. This framework allows us to make specific predictions pertaining to the mechanical properties which we can validate through deformation experiments performed in Molecular Dynamics simulations.