AC conductivity of Se-Ge-As glassy system in relation to rigidity percolation

Measurements of conductivity (ac & dc) and dielectric constant (epsilon) ha ve been made for amorphous alloyed samples of Se0.75Ge0.25-xAs(x) with x = 0.05, 0.10, 0.15 and 0.20 at different temperature (289 to 389 K) and vario us frequencies (10(2) to 10(5) Hz). The conductivity and the dielectric con stant of these glasses have been explained on the basis of the correlated b arrier hopping (CBH) model. Recent progress in applying percolation theory to explain properties and glass forming ability of chalcogenide glasses is critically reviewed. Percolation theory is shown to be relevant to the liqu id-state behavior of glass-forming ability of the Se-0.75Ge(0).25-xAs(x) ch alcogenide system. The relationship between the optical gap (DeltaE(g)) and chemical composition is also discussed in terms of the average heat of ato mization (H-s) and the average coordination number (r). These findings prov ide to some extent an important link between experimental and theoretical r esults. (C) 2001 Kluwer Academic Publishers.