On the influence of the initial liquid configuration on the structure of a glass obtained using ab-initio molecular dynamics simulations

We describe the effect of the cooling rate on some structural properties of GeS₂ chalcogenide glasses obtained using ab-initio molecular dynamics simulations. Quenches have been carried out using a linear velocity rescaling according to T(t) = T₀ − γt where γ is the cooling rate. In the present paper we discuss the influence of the initial liquid configuration on the structure of the GeS₂ glass. Structural properties of both liquid and glassy samples are compared. Furthermore a special attention is given to the total neutron structure factor. The decrease of the cooling rate appears in particular to improve the description of the medium range order of the glassy structure. The evolution of both intensity and position of the first sharp diffraction peak with the cooling rate also reveals that the influence of the initial configuration is very limited. Therefore our results confirm that in ab-initio molecular dynamics simulations as in experiment, the quench is the crucial step for structural changes between the liquid and the glassy phase.