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Low‐Temperature Anharmonicity in Cesium Chloride (CsCl)
Author(s) -
Sist Mattia,
Fischer Karl Frederik Færch,
Kasai Hidetaka,
Iversen Bo Brummerstedt
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201700638
Subject(s) - anharmonicity , chemistry , caesium , ionic bonding , diffraction , thermal conductivity , lattice vibration , ionic conductivity , thermal , analytical chemistry (journal) , crystallography , thermodynamics , condensed matter physics , ion , phonon , inorganic chemistry , physics , optics , organic chemistry , electrode , electrolyte
Anharmonic lattice vibrations govern heat transfer in materials, and anharmonicity is commonly assumed to be dominant at high temperature. The textbook cubic ionic defect‐free crystal CsCl is shown to have an unexplained low thermal conductivity at room temperature (ca. 1 W/(m K)), which increases to around 13 W/(m K) at 25 K. Through high‐resolution X‐ray diffraction it is unexpectedly shown that the Cs atomic displacement parameter becomes anharmonic at 20 K.