Unveiling the phonon scattering mechanisms in half-Heusler thermoelectric compounds

• Main Authors: He, Ran (Author), Zhu, Taishan (Author), Wang, Yumei (Author), Wolff, Ulrike (Author), Jaud, Jean-Christophe (Author), Sotnikov, Andrei (Author), Potapov, Pavel (Author), Wolf, Daniel (Author), Ying, Pingjun (Author), Wood, Max (Author), Liu, Zhenhui (Author), Feng, Le (Author), Rodriguez, Nicolas Perez (Author), Snyder, G Jeffrey (Author), Grossman, Jeffrey C (Author), Nielsch, Kornelius (Author), Schierning, Gabi (Author)
• Format: Article
• Language: English
• Published: Royal Society of Chemistry (RSC), 2022-05-17T18:41:36Z.
• Subjects: Article
• Online Access: Get fulltext

© The Royal Society of Chemistry. Half-Heusler (HH) compounds are among the most promising thermoelectric (TE) materials for large-scale applications due to their superior properties such as high power factor, excellent mechanical and thermal reliability, and non-toxicity. Their only drawback is the remaining-high lattice thermal conductivity. Various mechanisms were reported with claimed effectiveness to enhance the phonon scattering of HH compounds including grain-boundary scattering, phase separation, and electron-phonon interaction. In this work, however, we show that point-defect scattering has been the dominant mechanism for phonon scattering other than the intrinsic phonon-phonon interaction for ZrCoSb and possibly many other HH compounds. Induced by the charge-compensation effect, the formation of Co/4d Frenkel point defects is responsible for the drastic reduction of lattice thermal conductivity in ZrCoSb1-xSnx. Our work systematically depicts the phonon scattering profile of HH compounds and illuminates subsequent material optimizations. This journal is