Reverse Monte Carlo Simulations and Raman Scattering of an Amorphous GeSe${}_4$ Alloy Produced by Mechanical Alloying

The short and intermediate range order of an amorphous GeSe${}_4$ alloy produced by Mechanical Alloying were studied by Reverse Monte Carlo simulations of its x-ray total structure factor and Raman scattering. The simulations were used to compute the $G_{\text{Ge-Ge}}^{\text{RMC}}(r)$, $G_{\text{Ge-Se}}^{\text{RMC}}(r)$ and $G_{\text{Se-Se}}^{\text{RMC}}(r)$ partial distribution functions and the ${\cal S}^{$\text{RMC}$}{$\text{Ge-Ge}$}(K)$,${\cal S}^{$\text{RMC}$}{$\text{Ge-Se}$}(K)$and${\cal S}^{$\text{RMC}$}_{$\text{Se-Se}$}(K)$ partial structure factors. We calculated the coordination numbers and interatomic distances for the first and second neighbors and the bond-angle distribution functions ${\mathrm{\Theta }}_{ijl}(\cos \theta )$. The data obtained indicate that the structure of the alloy has important differences when compared to alloys prepared by other techniques. There are a high number of Se-Se pairs in the first shell, and some of the tetrahedral units formed seemed to be connected by Se-Se bridges.