Direct identification of the glass transition: Growing length scale and the onset of plasticity

¹  Department of Environmental Sciences and Energy, Weizmann Institute of Science - Rehovot 76100, Israel
²  The Department of Chemical Physics, The Weizmann Institute of Science - Rehovot 76100, Israel
³  Department of Physics, Emory University - Atlanta, Georgia 30322

Received: 30 November 2006
Accepted: 3 January 2007

Abstract

Understanding the mechanical properties of glasses remains elusive since the glass transition itself is not fully understood, even in well-studied examples of glass formers in two dimensions. In this context we demonstrate here: i) a direct evidence for a diverging length scale at the glass transition ii) an identification of the glass transition with the disappearance of fluid-like regions and iii) the appearance in the glass state of fluid-like regions when mechanical strain is applied. These fluid-like regions are associated with the onset of plasticity in the amorphous solid. The relaxation times which diverge upon the approach to the glass transition are related quantitatively to the diverging length scale.