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Accueil du site > Vie du Laboratoire > Archives > Archives 2013 "A la Une" >

29 octobre 2013

Clathrate Ba8Au16P30 : The “Gold Standard” for Lattice Thermal Conductivity

A novel clathrate phase, Ba8Au16P30, was synthesized from its elements. High-resolution powder X-ray diffraction and TEM were used to establish the crystal structure of the new compound. Ba8Au16P30 crystallizes in an orthorhombic superstructure of clathrate-I featuring a complete separation of gold and phosphorus atoms over different crystallographic positions, similar to the Cu-co ntaining analogue, Ba8Cu16P30. High-resolution STEM-HAADF indicated that the clathrate Ba8Au16P30 is well-ordered on the atomic scale, although numerous twinning and intergrowth defects as well as antiphase boundaries were dete cted. The presence of such defects results in the pseudo-bodycentered-cubic diffraction patterns observed in single-crystal X-ray diffraction experiments. NMR and resistivity characterization of Ba8Au16P30 indicated paramagnetic metallic properties with a room-temperature resistivity of 1.7 mΩ cm. Ba8Au16P30 exhibits a low total thermal conductivity (0.62 W m−1 K−1) and an unprecedentedly low lattice thermal conductivity (0.18 W m−1 K−1) at room temperature.

James Fulmer,Oleg I. Lebedev, Vladimir V. Roddatis, Derrick C. Kaseman, Sabyasachi Sen,
Juli-Anna Dolyniuk, Kathleen Lee, Andrei V. Olenev and Kirill Kovnir.

DOI : 10.1021/ja4052679