Chemical-pressure-induced point defects enable low thermal conductivity for Mg
Sn and Mg
Si single crystals
化学圧力誘起点欠陥によるMg
SnおよびMg
Si単結晶の低熱伝導率化
齋藤 亘*; 林 慶*; Huang, Z.*; 杉本 和哉*; 大山 研司*; 八方 直久*; 原田 正英
; 及川 健一
; 稲村 泰弘
; 林 好一*; 宮崎 孝道*; 宮崎 譲*
Saito, Wataru*; Hayashi, Kei*; Huang, Z.*; Sugimoto, Kazuya*; Oyama, Kenji*; Happo, Naohisa*; Harada, Masahide; Oikawa, Kenichi; Inamura, Yasuhiro; Hayashi, Koichi*; Miyazaki, Takamichi*; Miyazaki, Yuzuru*
The development of thermoelectric (TE) materials, which can directly convert waste heat into electricity, is vital to reduce the use of fossil fuels. Mg
Sn and Mg
Si are promising TE materials because of their superior TE performance. In this study, for future improvement of the TE performance, point defect engineering was applied to the Mg
Sn and Mg
Si single crystals (SCs) via boron (B) doping. Their crystal structures were analyzed via white neutron holography and SC X-ray diffraction. Moreover, nanostructures and TE properties of the B-doped Mg
Sn and Mg
Si SCs were investigated. The B-doping increased the chemical pressure on the Mg
Sn and Mg
Si SCs, leading to induce vacancy defects as a point defect. No apparent change was observed in electronic transport, but thermal transport was significantly prevented. This study demonstrates that the vacancy defects can be controlled by the chemical pressure, and can aid in achieving a high TE performance for the Mg
Sn and Mg
Si SCs.