在Mg3Sb2中,空位诱导的声子定位和格子软化,以减少导热率
Sheng Zhang1, Jinbao Zhang1, Liqi Ren1
1School of Intelligence Science and Technology, Nanjing University of Science and Technology, Jiangyin 214443, China.
Physical chemistry chemical physics : PCCP
|December 5, 2025
概括
抗氧化物 (Mg3Sb2) 是一个有前途的热电材料. Mg和Sb的空位通过散射声子显著降低其晶格导热率,为热性质控制提供了一条路径.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 固态化学 固态化学
背景情况:
- 抗氧化物 (Mg3Sb2) 是一个关键的中温热电材料,由于其自然丰富和低成本.
- 固有点缺陷,特别是空缺,在Mg3Sb2中普遍存在,并显著影响其热电性质.
- 这些空缺对格子导热率 (κL) 的确切影响需要进一步研究材料优化.
研究的目的:
- 研究 (Mg) 和反 (Sb) 的空缺对Mg3Sb2.2的晶格导热率 (κL) 的影响.
- 为了阐明微观机制,负责由于空缺的热传输观察到的变化.
- 评估缺陷工程对调整热电性能的潜力.
主要方法:
- 使用神经网络潜力 (NNP) 进行原子模拟.
- 分析了声分散,群体速度,平均平方位移 (MSD) 和声参与率 (PPR).
- 评估了弹性特性和原子间结合的变化.
主要成果:
- 无论是Mg还是Sb的空缺都会大大降低Mg3Sb2.2的晶格导热率 (κL).
- 增强的声子缺陷散射被确定为 κL 减少的主要机制.
- 空位诱导声软化,降低声组速度,并促进声定位.
结论:
- 点缺陷,特别是空缺,在降低Mg3Sb2.2.中的晶格导热率方面发挥着关键作用.
- 通过引入Mg和Sb空缺,缺陷工程是一种可行的策略,可以控制热电材料的热性能.
- 了解这些机制有助于设计更高效的热电设备.
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