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Direct observation of interstitial Mg atoms in stable high-performance n-type Mg₃Sb₂-based thermoelectric materials
S
J
郑
B
T
D
K
J
Q
Y
DOI:10.1016/j.scriptamat.2026.117535.png)
Abstract
En 中文
While interstitial Mg is thought to be key for n-type conduction of Mg3Sb2, direct experimental evidence of its presence remains lacking. In this work, we employ aberration-corrected scanning transmission electron microscopy to characterize the Pr0.03Mg3.2Sb1.5Bi0.5 sample at the atomic scale, and successfully obtain the direct observation of interstitial Mg occupancy. We find that Mg atoms simultaneously occupy two interstitial positions in the host lattice, and their incorporation ultimately causes slight distortion of the host lattice. What’s more, the sample exhibits long-term environmental stability and excellent thermal stability. This is evidenced by its maintenance of a high carrier concentration of 6×10¹⁹ cm−³ at 750 K even after 6-year ambient aging or 144 h annealing at 450°C, with only minor performance fluctuations. This discovery breaks through the long-standing reliance on indirect inference in the field, providing a new perspective for the design of high-performance, stable thermoelectric materials.
Keywords:
Thermoelectrics
Mg3Sb2
Property stability
Interstitial Mg
Journal
IF:
5.6
Papers:
1.6W
Citations:
5.1W
