The role of the structure and surface properties of Sn–Ge melts in the germanium crystallization

By analyzing the local atomic structure using models reconstructed from the experimental structure factor curves by the reverse Monte-Carlo method, we have established that microsegregation in the liquid state takes place in the Sn–Ge system and that tin and germanium atoms form chains with atomic spacings close to the covalent bond in solid state. The increase in the number of germanium atoms participating in cluster formation in diluted melts of germanium noticeably surpasses the increase in the germanium content of the melt, which is the reason for the appearance of extremums in the isotherms of density and surface tension of the Sn–Ge melt that is characterized by small positive deviations of activity from the ideal solution. In parallel with the interfacial energy and supersaturation, the cluster formation of the crystallizing substance with spacings close to the bond of this substance in the solid state contributes to an increase of the crystal growth rate.