A DFT Study on the Effects of Changing Transition Metals (Fe, Ru and Os) in Neodymium Phosphide Skutterudites NdTr4P12: Structural, Elastic, Thermodynamic, Electronic, Magnetic, Optical and Thermoelectric Properties

Several important ground state properties—structural, elastic, thermodynamic, electronic, magnetic, optical, and thermoelectric properties—of three neodymium-filled skutterudites NdTr₄P₁₂ (Tr = Fe, Ru, and Os) have been investigated using PBE-GGA exchange-correlation potential under the DFT method and Boltzmann transport theory. The effect of changing transition metals on these properties has been explored. Some of the physical parameters increase systematically with increasing atomic number (z) of the transition metals, while some other parameters exhibit a reverse trend. Although the band structure and DOS reveal their metallic nature, near the Fermi level total DOS are different in both spin channels. The materials are ferromagnetic and the magnetic moment of the compounds increases with z. The static dielectric constants also increase with z whereas the refractive indices in the optical frequency range decrease with z. The materials have high reflectivity and low absorption near the Fermi level and within the 0 – 5 eV spectral range, metal-insulator-metal type transition is seen in all. The thermoelectric figure of merit (ZT) increases fast with temperature but shows no systematic variation with z. In the high temperature range NdOs₄P₁₂ shows the maximum ZT value, followed by the ruthenium and iron compounds.