Journal Article

PUBDB-2022-02557

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

Xie, H. ; Bozin, E. S.Extern*XFEL.EU* ; Li, Z.Extern* ; Abeykoon, M. ; Banerjee, S.XFEL.EU*DESY* ; Male, J. P. ; Snyder, G. J. ; Wolverton, C. ; Billinge, S. J. L.Extern* ; Kanatzidis, M. G. (Corresponding author)

2022
Wiley-VCH Weinheim

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Please use a persistent id in citations: doi:10.1002/adma.202202255  doi:10.3204/PUBDB-2022-02557

Abstract: Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe$_2$ is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd$^3$ orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m$^{−1}$ K$^{−1}$ at 850 K in AgGaTe$_2$. The findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.

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Contributing Institute(s):

1. FS-Photon Science (FS-PS)
2. DOOR-User (DOOR ; HAS-User)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)

Experiment(s):

1. PETRA Beamline P21.1 (PETRA III)

Appears in the scientific report 2022

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF >= 25 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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