Improved thermoelectric property of Ti0.75HfMo0.25CrGe by doping Ti2CrGe Heusler alloy with Hf and Mo: Confirmation of entropy “gene” in thermoelectric materials design

Abstract

The electronic structure, thermoelectric properties, and thermodynamic entropy of Ti2CrGe-doped Ti0.75HfMo0.25CrGe were investigated using first-principles calculations in combination with the semi-classical Boltzmann transport theory and a common thermodynamic formalism. The band structure was half-metallic with a narrow gap of 0.02 eV in the spin-down channel and metallic character in the spin-up channel. The calculated thermoelectric transport properties revealed that Ti0.75HfMo0.25CrGe exhibited a larger thermoelectric figure of merit ZT with a lower lattice thermal conductivity than its prototype alloy Ti2CrGe. In particular, the entropy of Ti0.75HfMo0.25CrGe was larger than that of Ti2CrGe in the temperature range of 0–1000 K. These results indicate that increasing the entropy is an effective approach for the design of high-performance thermoelectric materials and confirm the entropy “gene” in thermoelectric materials.