Dong Zirui, Luo Jun, Wang Chenyang, Jiang Ying, Tan Shihua, Zhang Yubo, Grin Yuri, Yu Zhiyang, Guo Kai, Zhang Jiye, Zhang Wenqing
School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China.
Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
Nat Commun. 2022 Jan 10;13(1):35. doi: 10.1038/s41467-021-27795-3.
Half-Heusler and full-Heusler compounds were considered as independent phases with a natural composition gap. Here we report the discovery of TiRuSb (x = 0.15 ~ 1.0) solid solution with wide homogeneity range and tunable p- to n-type semiconducting thermoelectrics, which bridges the composition gap between half- and full-Heusler phases. At the high-Ru end, strange glass-like thermal transport behavior with unusually low lattice thermal conductivity (~1.65 WmK at 340 K) is observed for TiRuSb, being the lowest among reported half-Heusler phases. In the composition range of 0.15 < x < 0.50, TiRuSb shows abnormal semiconducting behaviors because tunning Ru composition results in band structure change and carrier-type variation simultaneously, which seemingly correlates with the localized d electrons. This work reveals the possibility of designing fascinating half-Heusler-like materials by manipulating the tetrahedral site occupancy, and also demonstrates the potential of tuning crystal and electronic structures simultaneously to realize intriguing physical properties.
半赫斯勒化合物和全赫斯勒化合物被视为具有天然成分间隙的独立相。在此，我们报告发现了具有宽均匀性范围和可调p型至n型半导体热电性能的TiRuSb（x = 0.15 ~ 1.0）固溶体，它弥合了半赫斯勒相和全赫斯勒相之间的成分间隙。在高Ru端，TiRuSb表现出奇特的类玻璃热输运行为，其晶格热导率异常低（340 K时约为1.65 WmK），是已报道的半赫斯勒相中最低的。在0.15 < x < 0.50的成分范围内，TiRuSb表现出异常的半导体行为，因为调节Ru成分会同时导致能带结构变化和载流子类型改变，这似乎与局域d电子有关。这项工作揭示了通过控制四面体位置占有率来设计迷人的类半赫斯勒材料的可能性，同时也展示了同时调节晶体和电子结构以实现有趣物理性质的潜力。
