Investigation of local structures and electronic states of Sb-doped Mg2Si by fluorescence XAFS and HAXPES

Tomoyuki Kadono, Naomi Hirayama, Tadashi Nishio, Shingo Yamazawa, Naoto Oki, Yoshinobu Takahashi, Natsumi Takikawa, Akira Yasui, Kiyofumi Nitta, Oki Sekizawa, Mako Tokumura, Shoji Takemoto, Tsutomu Iida, Masato Kotsugi

研究成果: Article査読

抄録

To clarify the origin of the figure of merit in the thermoelectric material Mg2Si, we performed extended X-ray absorption fine structure (EXAFS) analysis and hard X-ray photoelectron spectroscopy (HAXPES). We elucidate the local structures and electronic states of Mg2Si, especially focusing on the contribution of doped Sb. EXAFS analysis revealed that Sb substituted Si and that the nearest neighbor distance expanded around Sb. Furthermore, HAXPES confirmed the formation of density of states near the Fermi level by co-doping with 0.5% Zn and 0.5% Sb. The comparison of the experimental and theoretical results suggested that the density of states at the Fermi level was due to the tail of the conduction band, and it was filled by the electrons provided by doped Sb. From a microscopic viewpoint, the results obtained in this study suitably explain why Sb doping increases electrical conductivity and decreases thermal conductivity in Mg2Si, as reported in a previous study.

本文言語English
論文番号0018323
ジャーナルApplied Physics Letters
117
14
DOI
出版ステータスPublished - 5 10 2020

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