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Structural Complexity and Thermoelectric Properties of Quaternary and Quinary Tellurides (Ge x Sn 1– x ) 0.8 (In y Sb 1– y ) 0.13 Te with 0 ≤ x , y ≤ 1
Author(s) -
Neudert Lukas,
Schwarzmüller Stefan,
Scheel Manuel,
Welzmiller Simon,
Oeckler Oliver
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700337
Subject(s) - thermoelectric effect , materials science , quinary , van der waals force , condensed matter physics , vacancy defect , thermal conductivity , metastability , stoichiometry , seebeck coefficient , solid solution , scattering , electrical resistivity and conductivity , chalcogenide , lattice constant , crystallography , analytical chemistry (journal) , diffraction , chemistry , thermodynamics , physics , optics , metallurgy , organic chemistry , alloy , quantum mechanics , chromatography , molecule , composite material
Starting from stoichiometric mixtures of the elements, quaternary and quinary solid solutions (Ge x Sn 1– x ) 0.8 (In y Sb 1– y ) 0.13 Te were obtained. Concerning the ratio Ge/Sn and Sb/In, respectively, lattice parameters of the metastable phases with rocksalt‐type average structures approximately obey Vegard's law. Stable phases correspond to a disordered rocksalt type at high temperature and to trigonal layered structures with van der Waal gaps at lower temperature as shown by temperature‐dependent powder X‐ray diffraction combined with TEM, which reveals layer‐like vacancy ordering, whose extent depends on composition and thermal treatment. In the long‐periodically ordered model compounds 21 R ‐Ge 0.5 Sn 0.5 InSbTe 4 and 9 P ‐GeSnInSbTe 5 studied by resonant scattering data at K ‐absorption edges, Sb and Sn concentrate near the van der Waals gaps. Compared to Ge 0.8 Sb 0.13 Te and Sn 0.8 Sb 0.13 Te, the simultaneous presence of In and Sn combines increased electrical conductivity with low thermal conductivity and enhanced thermoelectric properties in certain temperature ranges. Phase transitions correlate with changes of the thermoelectric properties.