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)₄S₁₃ 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.

中文翻译：

---

摆脱压力：在平面协调中嘎嘎作响

热电设备将热流转换为电荷流，从而提供电力。用于高效设备的材料必须满足高电导率和低热导率的矛盾要求。已知笼状化合物的热导率会受到来宾原子的大振动（即所谓的“咔嗒声”）的抑制，从而有效地散射声子。这里，四面体（Cu，Zn）₁₂（Sb，As）₄ S ₁₃的晶体结构和声子动力学被研究。结果表明，Cu原子在平面配位过程中嘎嘎作响。与笼状化合物相反，化学压力会增大四面体中的嘎嘎声振动幅度，从而使嘎嘎声原子从平面配位体中挤出。此外，嘎嘎作响的振动通过金属对Sb和As的孤对震动邻居，这是造成四面体低热导率的原因。这些发现为开发具有平面配位的高效热电材料提供了新的策略。