Todorov Iliya, Chung Duck Young, Ye Linhui, Freeman Arthur J, Kanatzidis Mercouri G
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Inorg Chem. 2009 Jun 1;48(11):4768-76. doi: 10.1021/ic900035a.
We report the synthesis, structure, spectroscopic properties, charge and thermal transport, and electronic structure of a new member of the Zintl family, Yb(5)Al(2)Sb(6). The compound crystallizes in the Ba(5)Al(2)Bi(6) structure type and requires the addition of Ge or Si in the synthesis, which appears to act as a catalyst. Yb(5)Al(2)Sb(6) has an anisotropic structure with infinite anionic double chains cross-linked by Yb(2+) ions. Polycrystalline ingots of Yb(5)Al(2)Sb(6) prepared in the presence of 0.5 mol equiv of Ge showed room-temperature conductivity, thermopower, and thermal conductivity of approximately 1100 S/cm, approximately 20 microV/K, and approximately 3.8 W/m.K, respectively. Investigations of other solid solutions of Yb(5)Al(2)Sb(6), doping effects, and chemical modifications are discussed. Sr only partially replaces Yb in the structure leading to Sr(0.85)Yb(4.15)Al(2)Sb(6). Electronic structure calculations performed using a highly precise full-potential linearized augmented plane wave method within the density functional theory scheme show the presence of a negative band gap and suggest incomplete electron transfer and a metallic character to the compound.
我们报道了锌特耳（Zintl）家族新成员Yb(5)Al(2)Sb(6)的合成、结构、光谱性质、电荷与热传输以及电子结构。该化合物结晶为Ba(5)Al(2)Bi(6)结构类型，并且在合成过程中需要添加Ge或Si，它们似乎起到了催化剂的作用。Yb(5)Al(2)Sb(6)具有各向异性结构，由Yb(2+)离子交联形成无限的阴离子双链。在0.5摩尔当量的Ge存在下制备的Yb(5)Al(2)Sb(6)多晶锭在室温下的电导率、热电势和热导率分别约为1100 S/cm、约20 μV/K和约3.8 W/(m·K)。文中还讨论了对Yb(5)Al(2)Sb(6)的其他固溶体、掺杂效应和化学修饰的研究。Sr在结构中仅部分取代Yb，形成Sr(0.85)Yb(4.15)Al(2)Sb(6)。在密度泛函理论框架内使用高精度全势线性缀加平面波方法进行的电子结构计算表明存在负带隙，并表明该化合物存在不完全的电子转移且具有金属特性。
