High-Temperature Thermoelectric Properties of Polycrystalline Silicon Clathrate Ba^sub 8^TM^sub x^Si^sub 46-x^ (TM = Ni, Pt)

Issue Title: 2015 International Conference on Thermoelectrics. Guest Editors: Jihui Yang, Matt Beekman, Donald Morelli, James Salvador, David Singh, Hsin Wang, Emmanuel Guilmeau, Juri Grin, Bertrand Lenoir, Xinfeng Tang, Wenqing Zhang, Chunlei Wan, TieJun Zhu, Ryoji Funahashi, Takao Mori, Tsunehiro Takeuchi, Sabah Bux The n-/p-type stability of a silicon clathrate in which silicon was substituted with nickel or platinum was evaluated by density functional theory calculations. Then, Ba^sub 8^Pt^sub 5^Si^sub 41^ and Ba^sub 8^Pt^sub 1.5^Ni^sub 3.5^Si^sub 41^ were synthesized, and their thermoelectric properties were investigated. The polycrystalline compounds, which have a type-I clathrate structure, were prepared through arc melting and spark-plasma-sintering. The crystal structures and elemental compositions of the synthesized samples were characterized via powder x-ray diffraction and electron microprobe analyses, respectively. The temperature dependence of both the electrical resistivity and the Seebeck coefficient was measured.