Physicochemical Interactions in the GeSb2Te4–PbSb2Te4 System

Abstract

For the first time, the GeSb2Te4–PbSb2Te4 section of the GeTe–Sb2Te3–PbTe quasi-ternary system is investigated by complex methods of physicochemical analysis (differential thermal, microstructural, and X-ray phase analysis with microhardness measurement and density determination) and the phase diagram is constructed. It is established that the section is a partially quasi-binary section of the GeTe–Sb2Te3–PbTe quasi-ternary system. The GeSb2Te4-based region of the solid solution (15 mol % PbSb2Te4) is revealed. The congruently melting compound GePbSb4Te8 is formed with the ratio of the initial components 1:1. Single crystals of the GePbSb4Te8 quaternary compound are formed by the method of chemical transport reactions. The unit-cell parameters of the GePbSb4Te8 compound, which crystallizes in the orthorhombic crystal system, are determined: a = 5.06 A, b = 9.94 A, an c = 11.62 A. It is established by investigation of the temperature dependences of certain electrical parameters of the GePbSb4Te8 compound and (GeSb2Te4)x(PbSb2Te4)1 – x solid solution that the alloys have p-type conductivity.