Effect of metal doping on the low-temperature structural behavior of thermoelectric {beta}-Zn{sub 4}Sb{sub 3}

Journal Article · Sat Sep 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.07.013· OSTI ID:21043847

Nylen, Johanna; Lidin, Sven ^[1]; Andersson, Magnus ^[2]; Hongxue, Liu; Newman, Nate ^[3]; Haeussermann, Ulrich ^[4]

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1. Inorganic Chemistry, Stockholm University, SE-10691 Stockholm (Sweden)
2. Solid State Physics, IMIT, Royal Institute of Technology, KTH Electrum 229, SE-16440 Kista (Sweden)
3. School of Materials, Arizona State University, P.O. Box 876006, Tempe, AZ 85287-6006 (United States)
4. Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871604, Tempe, AZ 85287-1604 (United States)

The low-temperature structural phase transitions of Bi, Pb, In and Sn-doped samples of thermoelectric Zn{sub 4}Sb{sub 3} have been characterized on crystals grown from molten metal fluxes, using electrical resistance and single crystal X-ray diffraction measurements. Room temperature stable, disordered, {beta}-Zn{sub 4}Sb{sub 3} undergoes two phase transitions at 254 and 235 K to the consecutively higher ordered phases {alpha} and {alpha}', respectively. The ideal crystallographic composition of {alpha}-Zn{sub 4}Sb{sub 3} is Zn{sub 13}Sb{sub 10}. The {alpha}-{alpha}' transformation is triggered by a slight and homogenous Zn deficiency with respect to this composition and introduces a compositional modulation in the {alpha}-Zn{sub 4}Sb{sub 3} structure. When preparing {beta}-Zn{sub 4}Sb{sub 3} in the presence of metals with low melting points (Bi, Sn, In, Pb) the additional metal atoms are unavoidably incorporated in small concentrations (0.04-1.3 at%) and act as dopants. This incorporation alters the subtle balance between Zn disorder and Zn deficiency in Zn{sub 4}Sb{sub 3} and has dramatic consequences for its low-temperature structural behavior. From molten metal flux synthesis it is possible to obtain (doped) Zn{sub 4}Sb{sub 3} samples which (1) only display a {beta}-{alpha} transition, (2) only display a {beta}-{alpha}' transition, or (3) do not display any low-temperature phase transition at all. Case (2) provided diffraction data with a sufficient quality to obtain a structural model for highly complex, compositionally modulated, {alpha}'-Zn{sub 4}Sb{sub 3}. The crystallographic composition of this phase is Zn{sub 84}Sb{sub 65}. - Graphical abstract: The thermoelectric material Zn{sub 4}Sb{sub 3} displays complex temperature polymorphism. Room temperature stable, disordered, {beta}-Zn{sub 4}Sb{sub 3} undergoes two phase transitions at 254 and 235 K to the consecutively higher ordered phases {alpha} and {alpha}', respectively. The {alpha}-{alpha}' transformation is triggered by a slight and homogenous Zn deficiency and introduces a compositional modulation in the {alpha}-Zn{sub 4}Sb{sub 3} structure.

• OSTI ID: 21043847
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 9; Other Information: DOI: 10.1016/j.jssc.2007.07.013; PII: S0022-4596(07)00283-6; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIMONIDES
BISMUTH COMPOUNDS
CRYSTALLOGRAPHY
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
FLUX SYNTHESIS
INDIUM COMPOUNDS
LEAD COMPOUNDS
MELTING POINTS
MONOCRYSTALS
PHASE TRANSFORMATIONS
STRUCTURAL MODELS
TEMPERATURE RANGE 0273-0400 K
THERMOELECTRIC MATERIALS
TIN COMPOUNDS
X-RAY DIFFRACTION
ZINC COMPOUNDS