Short-range order and atomic diffusion in liquid Ge and $Si_{20}Ge_{80}$ investigated by neutron scattering and x-ray diffraction

We studied structure and dynamics in liquid Ge and Si$_{20}$Ge$_{80}$. Quasielastic neutron scattering (QNS) was employed to accurately determine the Ge self-diffusion coefficient. Static structure factors were measured using neutron and x-ray diffraction. Containerless processing via electromagnetic levitation (EML) enabled to obtain structure factors over a broad temperature range from the metastable regime of the undercooled melt to several hundred Kelvin above the melting point. Moreover, isotopic substitution and combination with x-ray diffraction allowed to determine the partial structure factors SNN(q), SNC(q), SGeGe(q), and SGeSi(q) for liquid $_{20}$Ge$_{80}$. The topological structures of liquid Ge and Si$_{20}$Ge$_{80}$ are very similar. In addition, the Ge self-diffusion coefficients in liquid Ge and Si$_{20}$Ge$_{80}$ are equal within error limits