Structural investigations of Ge ₅As _xSe _95-x and Ge ₁₅As _xSe _85-x glasses using x-ray diffraction and extended x-ray fine structure spectroscopy

The structure of Ge ₅As _xSe _95-x (x=10, 20, 30, 38at.%) and Ge ₁₅As _xSe _85-x (x=10, 25, 34at.%) glasses has been investigated by high-energy x-ray diffraction and extended x-ray absorption fine structure measurements. The experimental datasets have been modelled using the reverse Monte Carlo simulation technique. The model atomic configurations have been analysed in detail. It has been found that the homonuclear Ge-Ge, As-As, Se-Se and heteronuclear Ge-As bonds play an important role in the structure formation of the Ge-As-Se glasses. The total number of these bonds decreases quite slowly with the mean coordination number similarly to the nonlinear refractive index.