The cooling rate dependence of the shear modulus of amorphous solids

TL;DR

This paper investigates how the shear modulus of amorphous solids depends on cooling rate, revealing that the variation is mainly due to excess vibrational modes introduced by disorder, not the inherent Born term.

Contribution

It provides a quantitative analysis separating the Born term and excess modes, explaining the cooling rate dependence of shear modulus in glasses.

Findings

Born term is insensitive to cooling rate

Excess modes account for shear modulus variation

Provides a theoretical framework for understanding glass elasticity

Abstract

Rapidly cooling a liquid may result in a glass transition, creating an amorphous solid whose shear and bulk moduli are finite. Even when done with constant density, these resulting moduli depend strongly on the rate of cooling. Understanding this phenomenon calls for analyzing separately the "Born term" that exists also in perfectly ordered materials and the contributions of the "excess modes" that result from glassy disorder. We show that the Born term is very insensitive to the cooling rate, and all the variation in the shear modulus is due to the excess modes. We argue that this approach provides a quantitative understanding of the cooling rate dependence of a basic linear response coefficient, i.e. the shear modulus.