Mechanical and chemical thresholds in IV-VI chalcogenide glasses

It has been possible to identify two critical compositions in the IV-VI chalcogenide glassy system Ge<SUB>x</SUB>Se<SUB>100-x</SUB> by the anomalous variations of the high-pressure electrical resistivity behavior. The first critical composition, the chemical threshold, refers to the stoichiometric composition. The second critical composition, identified recently as the mechanical percolation threshold, is connected with the structural rigidity of the material