Type-I clathrate Ba8NixSi46-x: Phase relations, crystal chemistry and thermoelectric properties

Author(s)
Matthias Falmbigl, Mingxing Chen, Andrij Grytsiv, Peter Franz Rogl, Esmaeil Royanian, Herwig Michor, Ernst Bauer, Raimund Podloucky, Gerald Giester
Abstract

The phase relations, crystal structure and thermoelectric properties of the type-I solid solution Ba8NixSi46-x were investigated. Based on X-ray diffraction, differential thermal analysis and electron probe microanalysis data, a partial phase diagram was constructed for the Si-rich part of ternary system Ba-Ni-Si at 800 °C. The solubility range of Ni in the clathrate-I phase at 800 °C was determined (2.9 = x = 3.8) and thermoelectric properties, namely electrical resistivity, Seebeck-coefficient and thermal conductivity, were measured in the temperature range from 300 to 850 K. A shift of the thermoelectric properties from a predominantly metallic to a more semiconducting behavior was observed for an increasing Ni-content. Density functional calculations revealed a significant decrease of the gap width in the density of states induced by the incorporation of Ni. Electrical resistivity and Seebeck coefficients for Ba8NixSi46-x with 3.3 = x = 3.8 have been modeled within the rigid band approximation.

Organisation(s)
Department of Physical Chemistry, Department of Mineralogy and Crystallography
External organisation(s)
Technische Universität Wien
Journal
Dalton Transactions
Volume
41
Pages
8839-8849
No. of pages
11
ISSN
1477-9226
DOI
https://doi.org/10.1039/c2dt30279a
Publication date
2012
Peer reviewed
Yes
Austrian Fields of Science 2012
104017 Physical chemistry, 105113 Crystallography
Portal url
https://ucrisportal.univie.ac.at/en/publications/typei-clathrate-ba8nixsi46x-phase-relations-crystal-chemistry-and-thermoelectric-properties(2005eb85-9bc7-4f5e-b926-72e444de7f62).html