Title :
Temperature dependent structural and thermoelectric properties of Cs8Na16Si136 and Cs8Na16Ge136
Author :
Nolas, G.S. ; Vanderveer, D.G. ; Wilkinson, A.P. ; Cohn, J.L.
Author_Institution :
R&D Div., Marlow Industries Inc., Dallas, TX, USA
Abstract :
The temperature dependence of the atomic displacement parameters (ADPs) determined from single crystal x-ray diffraction data for Cs8Na16Si136 and Cs8Na16Ge136 as well as the thermoelectric properties of polycrystalline specimens is reported. Anomalously large values of the ADPs for the alkali-metal atoms are revealed. These data indicate that a large amount of dynamic disorder is associated with the "rattling" alkali-metal atoms inside the two different polyhedra that makeup the clathrate framework. Transport measurements show that these compounds are metallic conductors. The potential of type II clathrate materials for thermoelectric applications is also discussed
Keywords :
X-ray diffraction; caesium compounds; crystal structure; sodium compounds; thermoelectricity; Cs8Na16Ge136; Cs8Na16Si136; atomic displacement parameters; clathrate framework; dynamic disorder; metallic conductors; polycrystalline specimens; single crystal X-ray diffraction; temperature dependence; thermoelectric properties; type II clathrate materials; Atomic measurements; Bonding; Conducting materials; Crystalline materials; Crystals; Phonons; Physics; Temperature dependence; Thermoelectricity; X-ray diffraction;
Conference_Titel :
Thermoelectrics, 2001. Proceedings ICT 2001. XX International Conference on
Conference_Location :
Beijing
Print_ISBN :
0-7803-7205-0
DOI :
10.1109/ICT.2001.979881
