Defects of Non-Stoichiometry and Dynamic Stability of SnTe Crystal Lattice

The temperature dependencies of coefficient of linear expansion α in the range of 4.2-300 K were obtained for SnTe samples with various degrees of deviation from stoichiometry. For the sample of stoichiometric composition in the α vs. temperature curves the anomalies connected with ferroelectric phase transition were detected. It was found that within cubic phase existence region α isotherms have a minimum at 50.4 at.% Te. Maximum dynamic stability at indicated composition is believed to be associated with the formation of vacancy superstructure.