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

Measurements of conductivity (ac & dc) and dielectric constant (epsilon) have 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 various frequencies (10(2) to 10(5) Hz). The conductivity and the dielectric constant of these glasses have been explained on the basis of the correlated barrier 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 liquid-state behavior of glass-forming ability of the Se-0.75Ge(0).25-xAs(x) chalcogenide system. The relationship between the optical gap (DeltaE(g)) and chemical composition is also discussed in terms of the average heat of atomization (H-s) and the average coordination number (r). These findings provide to some extent an important link between experimental and theoretical results. (C) 2001 Kluwer Academic Publishers.