Enhanced Thermoelectric Properties at Low Temperatures in Heavy Fermion Compounds Ce_aSm_bEu_cYb_dIr₂Zn₂₀ (a + b + c + d = 1)

Thermoelectricity provides a green approach for efficient energy conversion. Applying a temperature gradient across a thermoelectric device produces an electric voltage and vice versa. As previously reported, heavy fermion 1-2-20 compounds show favorable thermoelectric properties at low temperatures. [1] In a typical 1-2-20 compound, the heavy rare earth elements are encompassed by large cage-like structures which provides an avenue for achieving reduced lattice component of the thermal conductivity. In addition, the strongly hybridized f-electron states at the Fermi level result in large Seebeck coefficient values. By varying the ratio among different rare earth elements in Ce_aSm_bEu_cYb_dIr₂Zn₂₀ (a + b + c + d = 1), we are able to modify the hybridization strength of the f-electron states and improve the Seebeck coefficient values. This contributes to the overall enhanced thermoelectric properties of these compounds. Characterization of these materials through thermal transport, magnetometry, EDS, and XRD will be discussed in detail.