Investigation of local surrounding of lead and selenium atoms in solid solution PbTe1-xSex by EXAFS technique

Investigation of local surrounding of lead and selenium atoms in the PbTe1-xSex solid solution is carried out through the EXAFS-spectroscopy method. High values of the Debye-Waller factors for the Pb-Pb interatomic distances (the second coordination sphere) and their noticeable deviation from the Vegard law were unexpectedly determined. The calculations, conducted through the Monte Carlo method, show, that the peculiarities observed are connected with the complex structure of the Pb-Pb distance distribution function. It is established, that the Se-Se pair number in the second coordination sphere exceeds the static value, which indicates the substantial role of chemical factors by forming the solid solution structure. The contribution of chemical factors to the enthalpy of solid solution mixing (≅ 0.5 kcal/mol)