Exploring potential thermoelectric materials: Electronic structure calculations of Y₃Ru₄Ge₁₃ and related compounds

We investigated the electronic structure and thermoelectric properties of potential thermoelectric materials by DFT calculations. The compounds analyzed have a general formula Y₃T₄(B1₁B2₁₂) (T = Ru or Co, and B = Ge, Sb, or Sn), which resembles filled skutterudites. We computed their band structure and projected density of states, as well as their Seebeck coefficients. All the explored materials had a metallic behavior, and exhibited a pseudo-gap in proximity of the Fermi level. The computed Seebeck coefficients were found to be strongly dependent upon the doping level, both in value and in sign. By optimizing the doping level we found excellent agreement with experimental data in a broad temperature range.