کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1332187 | 979032 | 2008 | 7 صفحه PDF | دانلود رایگان |
The new materials BaCuδAg2–δTe2 (0⩽δ⩽2) were prepared from the elements at 800 °C in evacuated silica tubes. BaAg2Te2 crystallizes in the α-BaCu2S2 type, space group Pnma, with lattice parameters a=10.8897(3) Å, b=4.6084(1) Å, c=11.8134(3) Å (Z=4). The structure consists of a three-dimensional network of vertex- and edge-condensed AgTe4 tetrahedra, which includes the Ba2+ cations in linear channels running along the short b-axis. Half of the Ag atoms participate in an Ag atom zigzag chain extended parallel to the channels. BaAg2Te2 is a p-type semiconductor with large Seebeck coefficient. Within the series BaCuδAg2−δTe2, the electrical conductivity increases and the Seebeck coefficient decreases strongly with increasing Cu content.
The tellurides BaCuδAg2−δTe2 all crystallize in the α-BaCu2S2 type. The Ag atoms prefer the M2 sites with short M–M bonds (solid lines). The materials are (degenerate) p-type semiconductors. Higher Ag content reflects itself in higher Seebeck coefficient and lower electrical conductivity.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 181, Issue 8, August 2008, Pages 2024–2030