Effect of Fe-Ru doping in the electronic and thermoelectric properties of new filled skutterudite Ba(Fe,Ru)_4As_(12)

摘要

We have performed the density functional theory based calculation to study the electronic and thermoelectric properties of BaFe_(4-x)Ru_xAs_(12) (x = 0%, 25%, 50%, 75%, and 100%) within the framework of the full potential-linearized augmented plane wave method. The composite alloys are found to be stable in their optimized crystal structures and their lattice constants are in close agreement with the corresponding experimental reports. The structural stability and mechanical properties are also studied using their elastic constants. The hardness of these materials increases with increasing concentration of Ru, which also donates the covalent nature of inter-atomic bonding of BaRu_4As_(12). The analysis of energy bands and density of states reflects the semi-metallic nature of BaFe_4As_(12) and BaRu_4As_(12), whereas other doped materials show metallic character. The electronic structure calculation suggests the high Seebeck coefficient with the efficient thermoelectric application of these materials. The thermal transport investigation also supports the result obtained from the electronic structure calculation. The thermoelectric efficiency defined by the figure of merit (ZT) of pure BaFe_4As_(12) (ZT= 0.004) and BaRu_4As_(12) (ZT =0.005) has been enhanced to 0.357 with 75% Ru doping. The spin-polarized calculation shows a significant effect on their energy band structure, giving magnetic behavior of the sample materials. The analysis of their magnetic profile suggests the ferromagnetic nature of these materials, except BaRu_4As_(l2), which shows a paramagnetic ground state.