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

Abstract

In this paper we explore the electronic nature and thermoelectric properties of filled skutterudites AFe(4)Sb(12) (A=Ca, 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/tau of 42.43 x 10(14) mu W/cmK(2)s and 33.57 x 10(14) mu W/cmK(2)s for the n-type of SrAFe(4)Sb(12) 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. (C) 2016 Elsevier B.V. All rights reserved.