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Evidence of Highly Anharmonic Soft Lattice Vibrations in a Zintl Rattler
Author(s) -
Dutta Moinak,
Samanta Manisha,
Ghosh Tanmoy,
Voneshen David J.,
Biswas Kanishka
Publication year - 2021
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.202013923
Subject(s) - anharmonicity , phonon , condensed matter physics , thermal conductivity , scattering , lattice (music) , materials science , excitation , inelastic neutron scattering , debye model , inelastic scattering , chemistry , crystallography , physics , optics , quantum mechanics , acoustics , composite material
Here, we present lattice dynamics associated with the local chemical bonding hierarchy in Zintl compound TlInTe 2 , which cause intriguing phonon excitations and strongly suppress the lattice thermal conductivity to an ultralow value (0.46–0.31 W m −1 K −1 ) in the 300–673 K. We established an intrinsic rattling nature in TlInTe 2 by studying the local structure and phonon vibrations using synchrotron X‐ray pair distribution function (PDF) (100–503 K) and inelastic neutron scattering (INS) (5–450 K), respectively. We showed that while 1D chain of covalently bondedI n T e 2n - ntransport heat with Debye type phonon excitation, ionically bonded Tl rattles with a frequency ca. 30 cm −1 inside distorted Thompson cage formed byI n T e 2n - n . This highly anharmonic Tl rattling causes strong phonon scattering and consequently phonon lifetime reduces to ultralow value of ca. 0.66(6) ps, resulting in ultralow thermal conductivity in TlInTe 2 .