|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Alloys and Compounds for Thermoelectric and Solar Cell Applications IX
||Using Neutrons to Probe the Influence of Processing on Temperature-dependent Strain in PbTe
||James Patrick Male, Riley Hanus, G Jeffrey Snyder, Raphael Hermann
|On-Site Speaker (Planned)
||James Patrick Male
Several recent breakthroughs in high zT PbTe-based materials reduce thermal conductivity by introducing dislocations. The defective core of a dislocation scatters phonons, while surrounding strain fields soften the lattice and reduce phonon velocity. The latter effect, lattice softening, accounts for much of the thermal conductivity reduction previously attributed to nanostructure phonon scattering in high zT PbTe. Through neutron diffraction experiments, we find that extensive ball milling doubles the amount of strain in undoped PbTe relative to nominally unstrained samples, but strain anneals out at high temperatures. Introducing extrinsic Eu and/or Na dopants increases the strain by another factor of two and assists in keeping strain in the sample at higher temperatures, which is desirable for high temperature performance. These results give direct insight into the ability to introduce and maintain strain in PbTe while providing direct explanations for impressively low thermal conductivities in recent groundbreaking PbTe-based materials.