Single crystal growth and characterization of new Zintl phase Ca9Zn3.1In0.9Sb9
Single crystal growth and characterization of new Zintl phase Ca9Zn3.1In0.9Sb9
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DOI：
10.1016/j.jssc.2020.121947
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发表时间：
2021-01
影响因子：
3.3
通讯作者：
David M. Smiadak;S. Baranets;Megan Rylko;M. Marshall;Mario Calderón-Cueva;S. Bobev;A. Zevalkink
中科院分区：
文献类型：
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作者：
David M. Smiadak;S. Baranets;Megan Rylko;M. Marshall;Mario Calderón-Cueva;S. Bobev;A. Zevalkink
复杂的 Zintl 相已经产生了多种有前途的新型热电材料。在这项研究中，我们报告了新 Zintl 相 Ca9(Zn1–xInx)4Sb9(x~ 0.9) 的发现，这种针状晶体是从富含 In 和 Sb 的熔剂中偶然获得的。尽管其成分让人想起Ca9Zn4+xSb9，这是一种zT>1的优异热电材料，但Zn位点上In的取代导致形成了全新的结构类型。单晶 X 射线衍射揭示了一种以 TSb4 四面体（T=统计无序的 Zn 和 In 原子）和 ZnSb3 三角形单元为特征的结构，它们共享公共角以形成 [T4Sb9]18− 聚阴离子。发现平均结构具有六方对称性。这种严重无序结构中的价电子计数似乎遵循 Zintl-Klemm 规则，表明半导体行为。单晶电导率和塞贝克系数测量支持这一结论，表明生长的晶体是简并p型半导体。
Complex Zintl phases have yielded a large variety of promising new thermoelectric materials. In this study we report the discovery of the new Zintl phase Ca9(Zn1–xInx)4Sb9(x~ 0.9), needle-like crystals of which were serendipitously obtained from an In- and Sb-rich flux. Although its composition is reminiscent of Ca9Zn4+xSb9, an excellent thermoelectric material withzT> 1, the substitution of In on the Zn site leads to the formation of an entirely new structure type. Single crystal X-ray diffraction revealed a structure characterized byTSb4tetrahedra (T= statistically disordered Zn and In atoms) and ZnSb3triangular units, which share common corners to form [T4Sb9]18−polyanions. The average structure was found to have hexagonal symmetry. The valence electron count in this heavily-disordered structure appears to follows the Zintl-Klemm rules, suggesting semiconducting behavior. Single crystal electrical conductivity and Seebeck coefficient measurements support this conclusion, suggesting that the as-grown crystals are degeneratep-type semiconductors.