Enhanced Thermoelectric Properties of A₁₋_𝑥B_𝑥Ir₂Zn₂₀ (A, B = Rare Earth) Through Chemical Substitution

Thermoelectric materials have important applications such as electric generators, refrigeration, and temperature sensing devices. The discovery of materials that have promising thermoelectric properties is possible through novel materials design and synthesis efforts. Chemical substitution has shown to be highly effective in optimizing the thermoelectric properties of certain materials. Specifically, this type of study has been utilized as a tuning parameter for enhancing the thermoelectric properties of the 1-2-20 class of compounds [1-3]. The heavy fermion nature accompanied by the enhanced scattering effects are the basis that make this group of compounds of great interest for thermoelectric applications. The electronic correlations associated with the f-elements gives rise to large Seebeck coefficient values, while the lattice structure supplies an environment that influences the phonon scatterings, which in turn reduces the thermal conductivity. These two aspects work together in these materials to enhance the thermoelectric figure of merit. Here we report on our latest investigation on the thermoelectric properties of A_1−𝑥B_𝑥Ir₂Zn₂₀ (A, B = Rare Earth) through a rare earth substitution series. These compounds were produced via the molten metal flux growth method, sample stoichiometry was determined through EDS, and the crystal structure was characterized using powder x-ray diffraction. The magnetic properties and the heat capacity of these samples will also be discussed in detail.



[1] Wei, et. al. Sci. Adv. 5, eaaw6183 (2019).

[2] Mun, et. al. Phys. Rev. B 86, 115110 (2012).

[3] Galeano-Cabral, et. al. Phys. Rev. Mater. 7, 25406 (2023).