论文标题
从变形的结晶α-MGAGSB中横向声音子抑制的超低热电导率
Ultralow thermal conductivity from transverse acoustic phonon suppression in distorted crystalline α-MgAgSb
论文作者
论文摘要
低热导率有利于保留热电材料两端之间的温度梯度，以确保电流连续发电。在高性能的热电材料中，有两个主要的低热导率机制：由AgCRSE2和CUCRSE2中的动态障碍引起的PBTE和SNSE和声子散射的声子Anharmonic，它们已通过非弹性中子散射成功地揭示了。使用中子散射和从头算计算，我们在这里报告了一种静态局部结构失真的机制，结合了α-MGAGSB中的声子 - 动物 - 动物触发诱导的超低晶格导热率。由于横向声音子几乎完全由该化合物的内在变形岩石sublattice完全散射，因此热量主要由纵向声音子运输。 α-MGAGSB中的超低热导率归因于其原子动力学因结构失真而改变，这可能会提高相似热电材料的性能的微观途径。
Low thermal conductivity is favorable for preserving the temperature gradient between the two ends of a thermoelectric material in order to ensure continuous electron current generation. In high-performance thermoelectric materials, there are two main low thermal conductivity mechanisms: the phonon anharmonic in PbTe and SnSe and phonon scattering resulting from the dynamic disorder in AgCrSe2 and CuCrSe2, which have been successfully revealed by inelastic neutron scattering. Using neutron scattering and ab initio calculations, we report here a mechanism of static local structure distortion combined with phonon-anharmonic-induced ultralow lattice thermal conductivity in α-MgAgSb. Since the transverse acoustic phonons are almost fully scattered by the compound's intrinsic distorted rocksalt sublattice, the heat is mainly transported by the longitudinal acoustic phonons. The ultralow thermal conductivity in α-MgAgSb is attributed to its atomic dynamics being altered by the structure distortion, which presents a possible microscopic route to enhance the performance of similar thermoelectric materials.
