Preferential substitution at cationic sites in 9-4-9 Zintl phase Ca9− yEuyZn4.5+ δ Sb9
Preferential substitution at cationic sites in 9-4-9 Zintl phase Ca9− yEuyZn4.5+ δ Sb9
复制标题
DOI：
10.1063/5.0147277
复制
发表时间：
2023-05
影响因子：
4
通讯作者：
Wenhua Xue;Honghao Yao;Chen Chen-Chen;Qian Zhang;Yumei Wang
中科院分区：
文献类型：
--
作者：
Wenhua Xue;Honghao Yao;Chen Chen-Chen;Qian Zhang;Yumei Wang
Ca_9Zn_（4.5）Sb_9 Zintl化合物是一种性能优良的热电材料，通过Eu合金化可以进一步提高其热电性能。本工作利用先进的铯校正高角度环形暗场扫描透射电子显微镜（HAADF-STEM）成像技术，在原子水平上对一系列Ca 9 − yEuyZn 4. 5 +δ Sb 9化合物进行了研究。HAADF-STEM图像表明，Eu的合金化将导致Eu原子在Ca（1）和Ca（5）位的优先取代。进一步的结构分析和第一性原理密度泛函理论计算阐明了Eu原子容易取代Ca（1）和Ca（5）位的原因。优先取代可能会提供一个新的见解揭示Zintl相热电材料中常见的结构转变。
Ca9Zn4.5Sb9 Zintl compound is one of the promising thermoelectric materials with excellent performance, which can be further improved by Eu alloying. In this work, a series of Ca9−yEuyZn4.5+δSb9 compounds is investigated by using the advanced Cs-corrected high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) imaging technique at an atomic level. The HAADF-STEM images show that alloying Eu will lead to preferential substitution of Eu atoms at Ca(1) and Ca(5) sites. The further structural analysis and first-principles density functional theory calculation elucidate the origin that the Eu atoms are prone to replace Ca(1) and Ca(5) sites in Ca9−yEuyZn4.5+δSb9. The preferential substitutions may provide a new insight into revealing the structural transformation commonly found in Zintl phase thermoelectric materials.