Sb置換されたTiNiSnハーフ・ホイスラー合金の熱電特性と電子構造

抄録

The thermoelectric properties of TiNiSn_1-xSb_x (0 ≤ x ≤ 0.05) prepared by arc melting are measured up to 800 K to obtain ZT. Hall effect measurements and ab initio calculation using AkaiKKR are performed to confirm the Sb substitution effect. The density of states before and after substitution show that Sb acts as a donor. Thermoelectric properties show that the absolute values of the electrical resistivity and Seebeck coefficient decreased with increasing x while the thermal conductivity increased. This is consistent with the carrier density-dependent trends when the carrier density increases. Hall effect measurements at room temperature also show that the carrier density increases with increasing x. Thus, the sample with the maximum ZT is TiNiSn_0.99Sb_0.01, with a value of ZT = 0.42 at 750 K. It can be said that Sb substitution for TiNiSn results in carrier doping and, at the optimum amount of substitution, improves the thermoelectric performance.