Thermoelectric properties of p-type half-Heusler compound HfPtSn and improvement for high-performance by Ir and Co additions

摘要

The authors found that the half-Heusler compound HfPtSn exhibits p-type thermoelectric behavior, contrary to the HfNiSn counterpart with the same valence electron count of 18 showing n-type behavior. Nearly single crystals of HfPtSn were fabricated using optical floating zone melting method. HfPtSn shows large thermoelectric power while its electrical resistivity and thermal conductivity are relatively high. They improved p-type thermoelectric properties of HfPtSn by the additions of Ir and Co for the Pt site. It aims not only to optimize carrier concentrations but also to suppress an increase in thermal conduction by reducing the lattice contribution through the solid solution effects.