M Bauchy, M Micoulaut
Université Pierre et Marie Curie-Paris VI
Publication year: 2012

Rigidity theory allows to predict the compositional behavior of many properties in glasses, while only considering their underlying network structure as simple mechanical trusses that can be exible, isostatic or stressed-rigid. Initially developped for chalcogenide glasses at zero temperature and ambient pressure, this theory has been progressively extended. In this thesis, we present a general method to analyze topological constraints from Molecular Dynamics simulations, this in order to be able to study the rigidity of more complex systems or experiencing new thermodynamical conditions. Thus, we show that our algorithm allows to study the rigidity of chalcogenide glasses as well as oxide glasses, while o ering a clear picture of the nature of the constraints at an atomic level. We also show that it makes it possible to follow their behavior with respect to composition, temperature and pressure. This method allows to track compositional rigidity transitions in systems and to highlight the existence of intermediate phases. We also report the existence of a pressure-induced intermediate phase and show that it is characterized by the same dynamical and structural signatures as usual intermediate phases driven by composition. Finally, we point out the strongly heterogeneous distribution of the constraints in the glassy network.