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

作者：Feng, Zhenzhen; Zhang, Jihua; Yan, Yuli; Zhang, Guangbiao; Wang, Chao; Peng, Chengxiao; Ren, Fengzhu; Wang, Yuanxu^*; Cheng, Zhenxiang^*

来源：Scientific Reports, 2017, 7(1): 2572.

DOI：10.1038/s41598-017-02808-8

• THERMAL-CONDUCTIVITY
• ELECTRONIC-STRUCTURE
• BANDS
• POWER
• OPTIMIZATION
• CONVERGENCE
• ENHANCEMENT
• TEMPERATURE
• TRANSPORT
• FIGURE

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 alpha-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 alpha-MgAgSb by increasing the number of band valleys near the Fermi level. For Li-doped alpha-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 alpha-MgAgSb with 14 conducting carrier pockets.

• 出版日期2017-5-31
• 单位河南大学