Ag-Mg antisite defect induced high thermoelectric performance of α-MgAgSb

Engineering atomic-scale native point defects has become an attractive strategy to improve the performance of thermoelectric materials. Here, we theoretically predict that Ag-Mg antisite defects as shallow acceptors can be more stable than other intrinsic defects under Mg-poor‒Ag/Sb-rich conditions....

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Bibliographic Details
Published in:Scientific reports 2017-05, Vol.7 (1), p.2572-12, Article 2572
Main Authors: Feng, Zhenzhen, Zhang, Jihua, Yan, Yuli, Zhang, Guangbiao, Wang, Chao, Peng, Chengxiao, Ren, Fengzhu, Wang, Yuanxu, Cheng, Zhenxiang
Format: Article
Language:English
Subjects:
119/118
639/301/119/995
639/301/299/2736
Conduction
Humanities and Social Sciences
multidisciplinary
Point defects
Science
Science (multidisciplinary)
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Summary:Engineering atomic-scale native point defects has become an attractive strategy to improve the performance of thermoelectric materials. Here, we theoretically predict that Ag-Mg antisite defects as shallow acceptors can be more stable than other intrinsic defects under Mg-poor‒Ag/Sb-rich conditions. Under more Mg-rich conditions, Ag vacancy dominates the intrinsic defects. The p -type conduction behavior of experimentally synthesized α-MgAgSb mainly comes from Ag vacancies and Ag antisites (Ag on Mg sites), which act as shallow acceptors. Ag-Mg antisite defects significantly increase the thermoelectric performance of α-MgAgSb by increasing the number of band valleys near the Fermi level. For Li-doped α-MgAgSb, under more Mg-rich conditions, Li will substitute on Ag sites rather than on Mg sites and may achieve high thermoelectric performance. A secondary valence band is revealed in α-MgAgSb with 14 conducting carrier pockets.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-017-02808-8