Effects of chemical potential on the thermoelectric performance of alkaline-earth based skutterudites (AFe4Sb12, ACa, Sr and Ba)

- All compounds are metallic in nature as investigated.
- Filing affects the valence band of the materials.
- Ba filed skutterudite BaFe4Sb12 show dense density of states close to the Fermi level.
- Thermoelectric performance of the materials is best in lower chemical potential region.
- SrFe4Sb12 shows good thermoelectric Power Factor results compared to CaFe4Sb12 and BaFe4Sb12.

In this paper we explore the electronic nature and thermoelectric properties of filled skutterudites AFe4Sb12 (ACa, Sr and Ba) by DFT and post-DFT techniques. The calculated results show that the filling of Ca, Sr, and Ba at the empty crystal sites enhances the thermoelectric performance of the host material. This increase is a consequence of the coupling between the guest and the host atoms, which affects the electronic density at different symmetry points that increases the density of states of the valence bands. The valence band edge is almost independent of the guest atoms, i.e., the s-bands of Ca, Sr and Ba have negligibly small contribution to the valence band edge. In these compounds, the maximum value of thermoelectric PF/τ of 42.43 × 1014 μW/cmK2s and 33.57 × 1014 μW/cmK2s for the n-type of SrFe4Sb12 in the spin-up and down states respectively. The striking feature of these compounds is their effectiveness at the low chemical potential values for the best thermoelectric performance.