Beneficial contribution of alloy disorder to electron and phonon transport in half-heusler thermoelectric materials

Hanhui Xie, Heng Wang, Yanzhong Pei, Chenguang Fu, Xiaohua Liu, G. Jeffrey Snyder, Xinbing Zhao, Tiejun Zhu*

*Corresponding author for this work

Research output: Contribution to journalArticle

245 Scopus citations

Abstract

Electron and phonon transport characteristics determines the potential of thermoelectric materials for power generation or refrigeration. This work shows that, different from most of high performance thermoelectric materials with dominant acoustic phonon scattering, the promising ZrNiSn based half-Heusler thermoelectric solid solutions exhibit an alloy scattering dominated charge transport. A low deformation potential and a low alloy scattering potential are found for the solid solutions, which is beneficial to maintain a relatively high electron mobility despite of the large effective mass, and can be intrinsic favorable features contributing to the noticeably high power factors of ZrNiSn based alloys. A quantitive description of the different phonon scattering mechanisms suggests that the point defect scattering is the most important mechanism that determines the phonon transport process of the solid solutions. The present results indicate that alloying can be an effective approach for such materials systems to enhance thermoelectric figure of merit ZT by reducing phonon thermal conductivity, while minimizing the deterioration of charge mobility due to the low alloy scatteirng potential. Alloy scattering dominated charge transport is found in the ZrNiSn thermoelectric solid solutions. A low deformation potential and a low alloy scattering potential are derived by a quantitative modeling of electrical transport properties, which is beneficial for a relatively high mobility. These intrinsic favorable features can contribute to the high power factors of the half-Heusler alloys.

Original languageEnglish (US)
Pages (from-to)5123-5130
Number of pages8
JournalAdvanced Functional Materials
Volume23
Issue number41
DOIs
StatePublished - Nov 6 2013

Keywords

  • alloys
  • charge transport
  • doping
  • thermoelectrics

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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