Peierls plasticity of thermoelectric lead telluride assessed by local misfit energy

Abstract

High brittleness observed in p-type PbTe is a significant obstacle in the commercial use of PbTe-based thermoelectric materials. An in-depth study of dislocations in PbTe is crucial due to their significant impact on material plasticity. In this work, the properties of 12[011](0 1¯ 1) edge dislocation in PbTe are investigated by using the local misfit energy of a shear model within the framework of the Peierls–Nabarro theory. By incorporating a moderate strain region size, a smooth and gradual transition of Pb–Te bonds during the shear process can be facilitated while balancing the elastic and inelastic components of the local misfit energy. The average misfit energy and the Peierls stress of the dislocation are calculated and compared with those of SrTiO3, a material that has demonstrated unexpected plasticity in its single crystal form. The findings indicate that undoped PbTe exhibits reasonably good plasticity. This work presents a theoretical approach to investigate dislocation properties in PbTe, laying the foundation for further research on the mechanical aspects of p-type dopant-induced issues in PbTe-based materials.