Phase stability and chemical composition dependence of the thermoelectric properties of the type-I clathrate Ba8AlxSi46-x (8≤x≤15)

Naohito Tsujii, John H. Roudebush, Alex Zevalkink, Catherine A. Cox-Uvarov, G. Jeffery Snyder, Susan M. Kauzlarich

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

Phase stability of the type-I clathrate compound Ba8Al xSi46-x and the thermoelectric property dependence on chemical composition are presented. Polycrystalline samples were prepared by argon arc melting and annealing. Results of powder X-ray diffraction and electron microprobe analysis show that the type-I structure is formed without framework deficiency for 8≤x≤15. Lattice constant a increases linearly with the increase of x. Thermoelectric properties were measured for x=12, 14 and 15. The Seebeck coefficients are negative, with the absolute values increasing with x. The highest figure of merit zT=0.24 was observed for x=15 at T=1000 K, with carrier electron density n=3×1021 cm-3. A theoretical calculation based on the single parabolic band model reveals the optimum carrier concentration to be n∼4×1020 cm -3, where zT∼0.7 at T=1000 K is predicted.

Original languageEnglish (US)
Pages (from-to)1293-1303
Number of pages11
JournalJournal of Solid State Chemistry
Volume184
Issue number5
DOIs
StatePublished - May 2011

Keywords

  • Clathrate compounds
  • Phase relation
  • Thermoelectric property

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Ceramics and Composites
  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry

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