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Quartic anharmonicity and ultra‐low lattice thermal conductivity of alkali antimonide compounds M 3 Sb ( M = K, Rb and Cs)
Author(s) -
Zhong Qi,
Dai Zhenhong,
Wang Weiqiang,
Zhao Yinchang,
Meng Sheng
Publication year - 2021
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.6284
Subject(s) - anharmonicity , antimonide , alkali metal , quartic function , condensed matter physics , thermal conductivity , phonon , lattice (music) , chemistry , thermoelectric materials , thermal stability , thermoelectric effect , materials science , thermodynamics , physics , organic chemistry , mathematics , acoustics , pure mathematics
Summary We investigate the role of the quartic anharmonicity in lattice dynamics and the thermal transport properties of the alkali antimonide compounds M 3 Sb ( M = K, Rb and Cs) by using the self‐consistent phonon theory combined with compressive sensing techniques. We found that the alkali‐metal atoms in K 3 Sb, Rb 3 Sb and Cs 3 Sb have a strong quartic anharmonicity and play a crucial role in the lattice dynamic stability. Based on the above results, the thermal transport properties are estimated with the relaxation time approximation of Boltzmann transport equation, the calculated lattice thermal conductivity κ L shows a remarkably low value at 300 K, which is 1.26, 0.63 and 0.52 Wm −1 K −1 for K 3 Sb, Rb 3 Sb and Cs 3 Sb, respectively. We have demonstrated the quartic anharmonicity of alkali antimonide compounds M 3 Sb ( M = K, Rb and Cs) and studied their thermal transport properties, which has never been reported before, the ultra‐low lattice thermal conductivity indicates that K 3 Sb, Rb 3 Sb and Cs 3 Sb are potential thermoelectric materials.