类金刚石
材料科学
四方晶系
双氰胺
热导率
对称性破坏
凝聚态物理
基态
结晶学
晶体结构
局部对称性
化学物理
分子
原子物理学
化学
物理
生物化学
离子液体
有机化学
量子力学
复合材料
催化作用
作者
Hongyao Xie,Emil S. Božin,Zhi Li,Milinda Abeykoon,Soham Banerjee,James P. Male,G. Jeffrey Snyder,Christopher Wolverton,Simon J. L. Billinge,Mercouri G. Kanatzidis
标识
DOI:10.1002/adma.202202255
摘要
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 AgGaTe2 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 sd3 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 AgGaTe2 . 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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