In:
Angewandte Chemie, Wiley, Vol. 134, No. 41 ( 2022-10-10)
Abstract:
Intrinsically low lattice thermal conductivity ( κ lat ) while maintaining the high carrier mobility ( μ ) is of the utmost importance for thermoelectrics. Topological insulators (TI) can possess high μ due to the metallic surface states. TIs with heavy constituents and layered structure can give rise to high anharmonicity and are expected to show low κ lat . Here, we demonstrate that Bi 1.1 Sb 0.9 Te 2 S (BSTS), which is a 3D bulk TI, exhibits ultra‐low κ lat of 0.46 Wm −1 K −1 along with high μ of ≈401 cm 2 V −1 s −1 . Sound velocity measurements and theoretical calculations suggest that chemical bonding hierarchy and high anharmonicity play a crucial role behind such ultra‐low κ lat . BSTS possesses low energy optical phonons which strongly couple with the heat carrying acoustic phonons leading to ultra‐low κ lat . Further, Cl has been doped at the S site of BSTS which increases the electron concentration and reduces the κ lat resulting in a promising n‐type thermoelectric figure of merit (zT) of ≈0.6 at 573 K.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v134.41
DOI:
10.1002/ange.202210783
Language:
English
Publisher:
Wiley
Publication Date:
2022
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