Enhanced thermoelectric properties of Ta-doped Half-Heusler ZrNiSn

Abstract

In the quest for more efficient thermoelectric material, the electrical contributions, namely the Seebeck coefficient, electrical conductance and electronic thermal conductance of Ta-doped ZrNiSn have been studied in the framework of Density functional theory (DFT). GGA formalism was used for exchange-correlation (XC) potentials within Perdew-Burke-Ernzerhof (PBE) parameterization. Boltzmann semi-classical transport equation (BTE) was used to study the thermoelectric properties like Power factor, electrical conductivity and thermal conductivity with respect to temperature and chemical potential. These properties were studied in temperature range from 300 K to 900 K. The value of electrical conductivity increases with doping. The value of electrical conductivity (σ/τ) for ZrNiSn at T = 300 K is 0.4 × 1018 S/cm.s and increases sharply to a value 73.9 × 1018 S/cm.s for Zr0.88Ta0.12NiSn. The electrical part of thermal conductivity (Ke/τ) increases with Ta-substitution. The increase in the value of electrical conductivity and Power factor on doping strongly suggest that Ta-doped ZrNiSn act as a potential material for thermoelectric applications.