Superior electron transport in the single-crystalline TiCoSb-based half-Heuslers

• DOI: 10.1038/s41467-025-56961-0
• Publication Date: 2025-02-24T10:05:22Z
• Authors: Sheng Ye; Shizhen Zhi; Xiaojing Ma; Xin Bao; Peng Zhao; Jinxuan Cheng; Sichen Duan; Chenhao Lin; Zuoxu Wu; Shanquan Chen; Jiamin Qiu; Li Yin; Xuanhe Zhang; Yifan Zhou; Feng Jiang; Zuhuang Chen; Feng Cao; Yuhao Fu; Qian Zhang; Jun Mao
• Keywords: Science; Q

Half-Heuslers emerged as promising candidates for medium- and high-temperature thermoelectric power generation. However, polycrystalline half-Heuslers inevitably suffer from the defect-dominated scattering of electrons that greatly limits optimization their electronic properties. Herein, high-quality TiCoSb-based single-crystals with a dimension above 1 cm have been obtained. Benefitting improved electron mobility, an average factor ~37 μW cm−1 K−2 in temperature range between 307 973 K has realized n-type single-crystalline Ti1-xNbxCoSb. In addition, Hf alloying results expansion weighted phase space enhances anharmonic rate, thereby effectively suppressing lattice thermal conductivity. Eventually, co-doping Nb/Ta elevate performance TiCoSb single crystal, peak zT 1.0 realized, which outperforms previously reported (Ti, Zr, Hf)CoSb-based ZrCoBi-based materials. Importantly, leg crystals exhibits heat-to-electricity energy conversive efficiency ~10.2% at difference 700 K. Here, our findings reveal promise generation, can potentially guide future explorations other half-Heuslers. The authors obtain exceeding cm, leading to extraordinary enhancement mobility consequently, 37 W Nb-doped single-crystal.