Contrasting role of bismuth doping on the thermoelectric performance of VFeSb half-Heusler

Nagendra S. Chauhan, Yuzuru Miyazaki

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Isoelectronic heavy elemental substitutions are generally preferred for enhancing the phonon scattering in a material without deteriorating its electrical transport. In this work, we demonstrate the efficacy and contrasting role of bismuth, an isoelectronic substitute of antimony, for enhancing the thermoelectric transport in structurally ordered cubic VFeSb half-Heusler. Despite its limited solubility, Bi-substitution at Sb-site, was found to be effective in enhancing the electrical power factor near room temperature. Alongside, synergistic lowering of lattice thermal conductivity was observed due to point defect scattering of phonons by Bi-induced mass and strain fluctuations. The electronic transport properties of nominal compositions and effects of Bi-doping induced disorder were evaluated using the Korringa–Kohn–Rostoker method with a coherent potential approximation (KKR-CPA). A highest thermoelectric figure-of-merit (zT) ~0.22 at 478 K was attained with improved weighted mobility and quality factor for optimally doped VFeSb0.98Bi0.02 half-Heusler alloy making them prospective compositions for near room temperature thermoelectric applications.

Original languageEnglish
Article number164623
JournalJournal of Alloys and Compounds
Volume908
DOIs
Publication statusPublished - 2022 Jul 5

Keywords

  • Bi-Doping
  • Density functional theory
  • Half-heusler
  • KKR-CPA
  • thermoelectrics

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