Investigating the Role of Vacancies on the Thermoelectric Properties of EuCuSb-Eu2ZnSb2 Alloys

Sevan Chanakian, Wanyue Peng, Vanessa Meschke, A. K.M. Ashiquzzaman Shawon, Jesse Adamczyk, Valeri Petkov, Eric Toberer, Alexandra Zevalkink

Research output: Contribution to journalArticlepeer-review


AMX compounds with the ZrBeSi structure tolerate a vacancy concentration of up to 50 % on the M-site in the planar MX-layers. Here, we investigate the impact of vacancies on the thermal and electronic properties across the full EuCu1−xZn0.5xSb solid solution. The transition from a fully-occupied honeycomb layer (EuCuSb) to one with a quarter of the atoms missing (EuZn0.5Sb) leads to non-linear bond expansion in the honeycomb layer, increasing atomic displacement parameters on the M and Sb-sites, and significant lattice softening. This, combined with a rapid increase in point defect scattering, causes the lattice thermal conductivity to decrease from 3 to 0.5 W mK−1 at 300 K. The effect of vacancies on the electronic properties is more nuanced; we see a small increase in effective mass, large increase in band gap, and decrease in carrier concentration. Ultimately, the maximum zT increases from 0.09 to 0.7 as we go from EuCuSb to EuZn0.5Sb.

Original languageEnglish
Article numbere202301176
JournalAngewandte Chemie - International Edition
Issue number29
StatePublished - Jul 17 2023


  • Defect Scattering
  • Thermoelectric Materials
  • Vacancies
  • Zintl Phases


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