Wang Wu, Liu Shixuan, Wang Yan, Jia Baohai, Huang Yi, Xie Lin, Jiang Binbin, He Jiaqing
Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
Shenzhen Institute for Advanced Study, University of Electronic Science and Technology of China, Shenzhen 518110, China.
Sci Adv. 2024 Jun 21;10(25):eadp4372. doi: 10.1126/sciadv.adp4372.
In high-entropy materials, local chemical fluctuation from multiple elements inhabiting the same crystallographic site plays a crucial role in their unique properties. Using atomic-resolution chemical mapping, we identified the respective contributions of different element characteristics on the local chemical fluctuation of high-entropy structures in thermoelectric materials. Electronegativity and mass had a comparable influence on the fluctuations of constituent elements, while the radius made a slight contribution. The local chemical fluctuation was further tailored by selecting specific elements to induce large lattice distortion and strong strain fluctuation to lower lattice thermal conductivity independent of increased entropy. The chemical bond fluctuation induced by the electronegativity difference had a noticeable contribution to the composition-dependent lattice thermal conductivity in addition to the known fluctuations of mass and strain field. Our findings provide a fundamental principle for tuning local chemical fluctuation and lattice thermal conductivity in high-entropy thermoelectric materials.
在高熵材料中，占据同一晶体学位置的多种元素引起的局部化学涨落在其独特性能中起着关键作用。通过原子分辨率化学映射，我们确定了不同元素特性对热电材料中高熵结构局部化学涨落的各自贡献。电负性和质量对组成元素的涨落影响相当，而半径的贡献较小。通过选择特定元素进一步调整局部化学涨落，以诱导大的晶格畸变和强烈的应变涨落，从而在不增加熵的情况下降低晶格热导率。除了已知的质量和应变场涨落外，由电负性差异引起的化学键涨落对成分依赖的晶格热导率有显著贡献。我们的研究结果为调节高熵热电材料中的局部化学涨落和晶格热导率提供了一个基本原理。
