Observation of a threshold behavior in the optical band gap and thermal diffusivity of Ge-Sb-Se glasses

Abstract

The optical band gap $(E_0)$ and thermal diffusivity (α) of bulk $Ge_xSb_5Se_{95-x}$ and $Ge_xSb_{10}Se_{90-x}$ glasses have been measured using the photoacoustic technique. The behavior of $E_0$ and α as the mean coordination number $\langle r \rangle$ is varied shows a maximum at $\langle r \rangle=2.6$. The anomalous behavior at $\langle r \rangle=2.6$ is explained on the basis of changes in the network topology due to the formation and development of layered structure in these glasses