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[摘要]：We have synthesized Tl(2)ZrTe(3) at elevated temperatures starting from the elements. Tl(2)ZrTe(3) adopts a cubic structure, space group P2(1)3 with a unit cell parameter of a = 19.118(1) angstrom (z = 36). All Tl and Zr atoms are octahedrally (distorted) coordinated by Te atoms. One out of 11 crystallographically distinct Te atoms in the structure is not connected to any Zr atoms, but is surrounded by six Tl atoms in the form of a severely distorted octahedron. Because of the absence of any significant homonuclear interactions, all atoms are in their most common oxidation states, namely, Tl(+), Zr(4+), and Te(2-). Electronic structure calculations and physical property measurements reveal the semiconducting characteristics of the compound. The structure and thermoelectric properties of Tl(2)ZrTe(3) and Tl(2)SnTe(3) are compared in the present work. The dimensionless figure of merit, ZT, was found to be 0.18 for Tl(2)ZrTe(3) at 420 K and 0.31 for Tl(2)SnTe(3) at 500 K, with both materials exhibiting very low thermal conductivity. Tl(2)ZrTe(3) decomposes irreversibly around 450 K in open systems under inert gas atmosphere, while it remains stable up to its incongruent melting point at 835 K in closed silica tubes. |
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