Synthesis and structure of layered compounds in the PbTe-Bi2Te3 and PbTe-Sb2Te3 systems

A number of tetradymite-like layered compounds in the PbTe-Bi₂Te₃ and PbTe-Sb₂Te₃ systems were prepared by a vertical Bridgman process, and their crystal structures were investigated by x-ray diffraction using single-crystal cleaved specimens. The atomic positional parameters and bond distances in PbBi₄Te₇ were determined. In the pseudobinary system PbTe-Sb₂Te₃, two new compounds were identified, PbSb₂Te₄ and PbSb₄Te₇, isostructural with PbBi₂Te₄ and PbBi₄Te₇, respectively. The positional parameters, site occupancies, and bond distances in the structure of PbSb₂Te₄ were determined. The room-temperature thermoelectric power of the grown ingots was measured along their length. All of the Sb compounds studied were found to be p-type, in contrast to the compounds of the PbTe–Bi₂Te₃ system.Translated from Neorganicheskie Materialy, Vol. 40, No. 12, 2004, pp. 1440–1447.Original Russian Text Copyright © 2004 by Shelimova, Karpinskii, Svechnikova, Avilov, Kretova, Zemskov.