2019/01/29 by Yandong Sun, Sun, Yandong, Yanguang Zhou +13
Engineering · Materials Science · #Advanced Thermoelectric Materials and Devices #Applied Physics (physics.app-ph) #FOS: Physical sciences #Thermal Radiation and Cooling Technologies #Thermal properties of materials
paper · pdf · doi:10.48550/arxiv.1901.10250
openalex publication_date 2019/01/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 1015m-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.