Structural and thermal investigations of an amorphous GaSe9 alloy using EXAFS, cumulant expansion, and reverse Monte Carlo simulations.

In this article, we investigated structural and thermal properties of an amorphous alloy of the Ga-Se system. The amorphous GaSe9 alloy was produced by mechanical alloying and it was studied using EXAFS spectroscopy and cumulant expansion method. We also made reverse Monte Carlo simulations using the total structure factor S(K) obtained from x-ray diffraction and the EXAFS _x(k) oscillations on Se and Ga K edges as input data. Several parameters, such as average coordination numbers and interatomic distances, structural and thermal disorders, asymmetry of the partial distribution functions _gij(r), and Einstein and Debye temperatures, were determined. The g_ij^E(r) functions were reconstructed from the cumulants C₁, C₂, and C₃ obtained from the Einstein model, and they were compared to the g_ij^RMC(r) functions obtained from the simulations. The simulations also furnished the partial bond angle distribution functions Θ_ijl(cos θ), which describe the angular distribution of bonds between first neighbors, and give information about the kind of structural units present in the alloy. [ABSTRACT FROM AUTHOR]