Xin Jia-Zhan, Fu Chen-Guang, Shi Wu-Jun, Li Guo-Wei, Auffermann Gudrun, Qi Yan-Peng, Zhu Tie-Jun, Zhao Xin-Bing, Felser Claudia
1Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
2State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China.
Rare Metals. 2018;37(4):274-281. doi: 10.1007/s12598-018-1027-9. Epub 2018 Apr 7.
Bismuth tellurohalides with Rashba-type spin splitting exhibit unique Fermi surface topology and are developed as promising thermoelectric materials. However, BiTeBr, which belongs to this class of materials, is rarely investigated in terms of the thermoelectric transport properties. In the study, polycrystalline bulk BiTeBr with intensive texture was synthesized via spark plasma sintering (SPS). Additionally, its thermoelectric properties above room temperature were investigated along both the in-plane and out-plane directions, and they exhibit strong anisotropy. Low sound velocity along two directions is found and contributes to its low lattice thermal conductivity. Polycrystalline BiTeBr exhibits relatively good thermoelectric performance along the in-plane direction, with a maximum dimensionless figure of merit (ZT) of 0.35 at 560 K. Further enhancements of ZT are expected by utilizing systematic optimization strategies.
具有Rashba型自旋分裂的铋碲卤化物展现出独特的费米面拓扑结构，并被开发为有前景的热电材料。然而，属于这类材料的BiTeBr在热电输运性质方面却很少被研究。在本研究中，通过放电等离子烧结（SPS）合成了具有强烈织构的多晶块状BiTeBr。此外，研究了其在室温以上沿面内和面外方向的热电性质，结果显示出很强的各向异性。发现沿两个方向的声速较低，这有助于降低其晶格热导率。多晶BiTeBr沿面内方向展现出相对良好的热电性能，在560 K时最大无量纲品质因数（ZT）为0.35。通过采用系统的优化策略有望进一步提高ZT值。
