Dislocations can greatly enhance the figure of merit of thermoelectric materials by prominently reducing thermal conductivity. However, the evolution of phonon modes with different energies when they propagate through a single dislocation is unknown. Here we perform non-equilibrium molecular dynamics simulation to study phonon transport in PbTe crystal with dislocations by excluding boundary scattering and strain coupling effect. The frequency-dependent heat flux, phonon mode analysis, and frequency-dependent phonon mean free paths (MFPs) are presented. The thermal conductivity of PbTe with dislocation density on the order of 10¹⁵ m⁻² is decreased by 62%. We provide solid evidence of strong localization of phonon modes in dislocation sample. Moreover, by comparing the frequency-dependent phonon MFPs between atomistic modeling and traditional theory, it is found that the conventional theories are inadequate to describe the phonon behavior throughout the full phonon spectrum, and large deviation to the well-known semi-classical Matthiessen’s rule is observed. These results provide insightful guidance for the development of PbTe based thermoelectrics and shed light on new routes for enhancing the performance of existing thermoelectrics by incorporating dislocations.

位错可通过显着降低热导率来大大提高热电材料的品质因数。然而，当声子模通过单个位错传播时，具有不同能量的声子模的演化是未知的。在这里，我们进行非平衡分子动力学模拟，以通过排除边界散射和应变耦合效应来研究具有位错的PbTe晶体中的声子传输。给出了频率相关的热通量，声子模式分析和频率相关的声子平均自由程（MFP）。位错密度约为10 ¹⁵  m ^-2的PbTe的热导率减少了62％。我们提供了位错样本中声子模强定位的有力证据。此外，通过将原子建模与传统理论之间的频率相关声子MFP进行比较，发现传统理论不足以描述整个声子谱中的声子行为，并且与著名的半经典Matthiessen法则有很大的偏差。被观察到。这些结果为基于PbTe的热电学的发展提供了有见地的指导，并为通过结合位错来增强现有热电学性能的新途径提供了启示。