Predicting the Thermoelectric Performance of p-type VFeBi Based on Scattering Mechanisms

Acoustic phonon scattering is mostly regarded as the deciding scattering in half-Heusler studies. This oversimplification needs scrutiny because there are other scatterings which might be more prominent. If other scattering mechanisms are ignored, the calculation results may be affected. In this paper, we systematically study the electronic structure, dynamic stability, and thermoelectric properties of the p-type VFeBi compound based on three scattering mechanisms: acoustic phonon, ionized impurity, and polar optical phonon. We analyze the change of electronic transport parameters under different combinations of the three scattering mechanisms to explore the effects of different scattering on thermoelectric performance. The results show that, in addition to an acoustic phonon, ionized impurity and polar optical phonon also have a significant impact on thermoelectric performance. With the increase in scattering mechanism, the mobility, electronic conductivity, power factor, and electronic thermal conductivity gradually decrease. It can be shown that the predicted ZT of p-type VFeBi under the acoustic phonon and polar optical phonon scattering can reach up to 2.431 at 1.07 × 1020 cm−3 and 875 K, while it is 2.47 under the three scatterings at 1.14 × 1020 cm−3 and 910 K. However, the maximum value of ZT is 3.424 under acoustic phonon scattering at 5.48 × 1019 cm−3 and 784 K. Therefore, it is inaccurate to only consider acoustic phonon scattering. Comparing the ZT values under different conditions, we predict that the p-type VFeBi compound has a good thermoelectric performance.