Theoretical investigation of the ultralow thermal conductivity of 2D PbTe via a strain regulation method

Abstract

To systematically develop an efficient computational protocol for discovering high-performance materials with desirable thermal conductivity, it is essential to theoretically understand the key factors influencing their heat transport capacity. Recent advancements in first-principles based calculations have significantly facilitated the exploration of structural and electronic properties of nanoscale devices. Efficient identification of the dominant factors impacting the materials' inner heat transport is crucial for their applications in real practice. In this study, we optimized our computation protocol originally proposed for thermal conductivity investigations and extended it to explore heat transport within a 2-dimensional (2D) alloying material, PbTe. We delved into the structural and electronic properties of PbTe in detail. Additionally, to assess the thermodynamic stability and describe the bonding network of this 2D alloying material, we calculated its phonon dispersion at different strains. The heat transport mechanism within PbTe has been systematically investigated. The insights gained from this work are instructive for future studies, particularly those focusing on the evaluation of 2D materials’ thermoelectric performance. This research contributes to a broader understanding of how structural and electronic properties influence the inner heat transport of 2D materials, establishing a theoretical foundation for the development of high-performance thermal devices.