Zn13Sb10:: A structural and Landau theoretical analysis of its phase transitions
Zn13Sb10:: A structural and Landau theoretical analysis of its phase transitions
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DOI：
10.1021/cm0515505
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发表时间：
2006-02-07
影响因子：
8.6
通讯作者：
Miller, GJ
中科院分区：
文献类型：
--
作者：
Mozharivskyj, Y;Janssen, Y;Miller, GJ
在多晶样品和铋助熔剂生长的单晶上，用X射线衍射技术、电阻和塞贝克系数测量，研究了在4-773K的不同温度下，热电材料的组成、晶体结构、多晶型转变和稳定性。微探针分析表明，助熔剂生长的晶体的成分接近于Zn13Sb10，掺杂少量的铋。高温X射线和Seebeck系数研究表明，由于锌的损失，该相在真空中高温下是不稳定的。X射线衍射和电阻率测量都表明，在室温下存在两个连续的对称性破缺转变，这与我们之前对多晶样品的结果一致。朗道理论的应用表明，第一次R3c->；C2/c对称性破缺本质上可能是二级的。第二，低温对称性破缺可以沿着两条路线进行。其中一条途径是一阶C2/c-C1对称性约化，可能导致无公度结构，这与我们的实验观察是一致的。
Composition, crystal structures, polymorphic transformations, and stability of the thermoelectric material known in the literature as "Zn4Sb3" have been studied on a polycrystalline sample and Bi-flux-grown single crystals using X-ray diffraction techniques, resistance, and Seebeck coefficient measurements at various temperatures ranging from 4 to 773 K. Microprobe analysis yields the composition of the fluxgrown crystals to be close to Zn13Sb10, with minor Bi doping. High-temperature X-ray and Seebeck coefficient studies show that the phase is unstable at high temperatures in a vacuum because of Zn losses. Both X-ray diffraction and resistivity measurements indicate the presence of two consecutive symmetry-breaking transitions below room temperature, in agreement with our previous results on polycrystalline samples. Application of Landau theory suggests that the first R3c -> C2/c symmetry breaking may be second-order in nature. The second, low-temperature symmetry breaking may proceed along two routes. One of these pathways, a first-order C2/c - C1 symmetry reduction, may lead to an incommensurate structure and is consistent with our experimental observations.