Anomalous X-ray scattering studies on glassy Ge Se1− over a wide concentration range including the stiffness transition composition

Anomalous X-ray scattering experiments on glassy Ge x Se 1-x have been carried out at energies close to the Ge and Se K edges in a wide concentration range from x = 0.15 to 0.333 across the stiffness transition composition. The total structure factors S(Q) show considerable variations in both the position and intensity of the prepeak around 10 nm -1 , while in the remaining Q range, it stays almost unchanged. The differential structure factors Δ i S(Q) comprise characteristic features. Comparing them suggests that the prepeak purely originates from the Ge-Ge correlation. The concentration dependence of the prepeak is consistent with Raman data, which reveal the diminishing of short Se chain connections between the Ge(Se 1/2 ) 4 tetrahedra near the stiffness transition composition.