We report the synthesis, structure, spectroscopic properties, charge and thermal transport, and electronic structure of a new member of the Zintl family, Yb 5AI 2Sb 6. The compound crystallizes in the Ba 5AI 2Bi 6 structure type and requires the addition of Ge or Si in the synthesis, which appears to act as a catalyst. Yb 5AI 2Sb 6 has an anisotropic structure with infinite anionic double chains cross-linked by Yb 2+ ions. Polycrystalline ingots of Yb 5Al 2Sb 6 prepared in the presence of 0.5 mol equiv of Ge showed room-temperature conductivity, thermopower, and thermal conductivity of ∼1100 S/cm, ∼20 μV/K, and ∼3.8 W/m K, respectively. Investigations of other solid solutions of Yb 5AI 2Sb 6, doping effects, and chemical modifications are discussed. Sr only partially replaces Yb in the structure leading to Sr 0.85Yb 4.15AI 2Sb 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.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry