Structure transition and thermoelectric properties related to AZn(1-x)/2CuxSb (A=Ca,Eu,Sr; 0
Structure transition and thermoelectric properties related to AZn(1-x)/2CuxSb (A=Ca,Eu,Sr; 0
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AZn(1-x)/2CuxSb (A=Ca,Eu,Sr; 0) 相关的结构转变和热电性能
DOI：
10.1016/j.jallcom.2019.152508
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发表时间：
2019
影响因子：
6.2
通讯作者：
Xia Shengqing
中科院分区：
文献类型：
--
作者：
Zhang Jian;Liu Xiaocun;Liu Qian;Xia Shengqing
据报道，通式ACuSb（A=Ca、Sr、Eu）的含铜锑化合物采用ZrBeSi结构类型，其特征是由蜂窝状Cu3Sb3环组成的平面CuSb层。含锌类似物也可以以这种结构类型结晶，但过渡金属位点占据约 50%，并且是无序的 A2ZnSb2 结构。有趣的是，当Cu和Zn同时纳入阴离子结构时，证明了从ZrBeSi型到LiGaGe型的相变，从而发现了一系列新的Cu/Zn混合Zintl相，CaZn0.36(1)Cu0.28(1)Sb、EuZn0.25(3)Cu0.50(3)Sb和SrZn0.17(3)Cu0.65(3)Sb。通过单晶X射线衍射方法准确测定了这些新相的晶体结构，表明P63mc(no. 186)空间群的晶胞参数为：a=4.5234(3)/4.5705(6)/4.5863(9) Å，对于Ca-，c=7.9562(10)/8.431(2)/8.698(3) Å，分别含Sr和Eu的化合物。采用名义上成分相同的材料 AZn0.25Cu0.5Sb（A=Ca、Sr、Eu）系统地研究了热电性能。通过基于Sr化合物构建的各种模型进行电子能带结构计算，这表明随着从ZrBeSi型到LiGaGe型的结构转变，价带显着收敛。
The copper-containing antimony compounds with the general formulae ACuSb (A = Ca, Sr, Eu) were reported to adopt the ZrBeSi structure type, which feature a planar CuSb layer composed of honeycomb-like Cu3Sb3rings. The Zn-containing analogues can crystallize in such a structure type too, but with ∼50% occupancy at the transition metal site and a disordered A2ZnSb2structure. Interestingly, phase transition was proven from the ZrBeSi type to the LiGaGe type when Cu and Zn were both incorporated in the anionic structure, which led to the discovery of a series of new Cu/Zn-mixed Zintl phases, CaZn0.36(1)Cu0.28(1)Sb, EuZn0.25(3)Cu0.50(3)Sb and SrZn0.17(3)Cu0.65(3)Sb. The crystal structures of these novel phases were accurately determined through the single-crystal X-ray diffraction method, which indicated theP63mc(no. 186) space group with cell parameters:a= 4.5234(3)/4.5705(6)/4.5863(9) Å andc= 7.9562(10)/8.431(2)/8.698(3) Å for the Ca-, Sr- and Eu-containing compounds, respectively. Thermoelectric properties were systematically investigated by materials AZn0.25Cu0.5Sb (A = Ca, Sr, Eu) with nominally the same compositions. Electronic band structure calculations were performed by various models constructed based on the Sr compounds, which suggested significant convergence of the valence bands with structure transition from the ZrBeSi type to the LiGaGe type.