Rigidity transitions and intermediate structures of Ge-Se glasses - An anomalous X-ray scattering study

摘要

Anomalous X-ray scattering experiments on glassy Ge_xSe_(l-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 rigidity percolation threshold. 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_iS(Q) comprise characteristic features. Comparing them suggests that the prepeak purely originates from the Ge-Ge correlation. The threshold is characterized by the percolation of two-Se-linked Ge(Se_(1/2))_4 tetrahedra distributed all over the network as proposed by Feltz et al.