立方体GeMnTe₂の不調和歪みとGeMnTe₂の高熱電気特性-%SbTe

Jinfeng Dong^1,2, Yilin Jiang¹, Yandong Sun³

¹State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.

Journal of the American Chemical Society

|January 17, 2023

まとめ

熱電性物質であるGeMnTe2は局所的な歪みを示しています SbTeを合金することで熱電性能が向上し,シーベック係数と低熱伝導性により,ZT値は約1.5に達する.

科学分野:

材料科学
固体物理学
熱電機

背景:

GeMnTe2は岩塩の立方体構造を示し,中温熱電学的用途に適しています.
ニュートロン散乱データは,理想的な八面体位置から移動したGe2+カチオンで,GeMnTe2の局所的な歪みを明らかにします.

研究の目的:

GeMnTe2の熱電特性に対するSbTe合金の効果を調査する.
強化された熱電性能の構造的および電子的起源を理解する.

主な方法:

ニュートロン総散乱データのペア分布関数解析
GeMnTe2とSbTeを合金して,キャリア濃度を調節する.
シーベック係数,功率因数,熱伝導率を含む熱電特性に関する記述.

主要な成果:

GeMnTe2-15.1%SbTeは,広範囲の温度 (300~823K) で高いシーベック係数 (>200μV K-1) を示しています.
合金は,高密度状態の有効質量と高重量移動性を示し,結果として823Kで15μWcm-1K-2の功率因子を示しています.
823 Kの非常に低い格子熱伝導度 (~0.5 Wm-1 K-1) は,構造的障害とナノ粒子に起因する.
400〜823Kの間には,ピークZT値約1. 5と平均ZT (ZTave) 0. 96が達成された.

結論:

SbTe合金は,GeMnTe2の電子構造を効果的に調節し,その熱電特性を増強します.
構造的な複雑さ,中心外カチオンおよび乱れは,格子熱伝導性を大幅に低下させる.
最適化されたGeMnTe2-15.1%SbTe組成は,効率的な中温熱電性材料としての大きな可能性を示している.

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