Enhanced thermoelectric performance of Zr_1−xNiSnTa_x half-Heusler alloys: a first-principle study

First-principles calculations combined with the Boltzmann transport theory were used to calculate the thermoelectric characteristics of Zr_1−xNiSnTa_x (x = 0, 1/4, 1/8, 1/12, 1/16, 1/24, 1/32, 1/36, 1/48, and 1/64). Ta-doped ZrNiSn can effectively improve the Seebeck coefficient of Zr_1−xNiSnTa_x, and it can also reduce its thermal conductivity. The maximum Seebeck coefficients of p-type and n-type Zr_3/4NiSnTa_1/4 are 1117.58 μV/K and − 1059.47 μV/K, respectively. The maximum thermoelectric figure of merit of the p-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.98, and the maximum thermoelectric figure of merit of the n-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.97. The optimum thermoelectric figure of merit of Zr_1−xNiSnTa_x studied in this paper is higher than those of other studies. Our results demonstrate the good potential thermoelectric material of Zr_1−xNiSnTa_x for thermoelectric device applications.