Retreat from Stress: Rattling in a Planar Coordination
Retreat from Stress: Rattling in a Planar Coordination
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DOI：
10.1002/adma.201706230
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发表时间：
2018-03-27
影响因子：
29.4
通讯作者：
Takabatake, Toshiro
中科院分区：
文献类型：
--
作者：
Suekuni, Koichiro;Lee, Chul Ho;Takabatake, Toshiro
热电装置将热流转换为电荷流，从而提供电力。用于高效器件的材料必须满足高电导率和低热导率的矛盾要求。众所周知，笼状化合物的热导率会被客体原子的大振动（所谓的嘎嘎声）抑制，这种振动有效地散射了声子。本文研究了（Cu，Zn）（12）（Sb，As）（4）S-13的晶体结构和声子动力学。结果表明，铜原子在平面配位中是晃动的。与笼状化合物相比，化学压力增大了四面体中振动的振幅，使得振动原子被挤出平面配位。此外，嘎嘎振动通过类金属Sb和As的孤对振动邻居，这是造成四面体的低热导率的原因。这些发现为开发具有平面配位的高效热电材料提供了一种新的策略。
Thermoelectric devices convert heat flow to charge flow, providing electricity. Materials for highly efficient devices must satisfy conflicting requirements of high electrical conductivity and low thermal conductivity. Thermal conductivity in caged compounds is known to be suppressed by a large vibration of guest atoms, so-called rattling, which effectively scatters phonons. Here, the crystal structure and phonon dynamics of tetrahedrites (Cu,Zn)(12)(Sb,As)(4)S-13 are studied. The results reveal that the Cu atoms in a planar coordination are rattling. In contrast to caged compounds, chemical pressure enlarges the amplitude of the rattling vibration in the tetrahedrites so that the rattling atom is squeezed out of the planar coordination. Furthermore, the rattling vibration shakes neighbors through lone pairs of the metalloids, Sb and As, which is responsible for the low thermal conductivity of tetrahedrites. These findings provide a new strategy for the development of highly efficient thermoelectric materials with planar coordination.