Gao Wenshuai, Hao Ningning, Zheng Fa-Wei, Ning Wei, Wu Min, Zhu Xiangde, Zheng Guolin, Zhang Jinglei, Lu Jianwei, Zhang Hongwei, Xi Chuanying, Yang Jiyong, Du Haifeng, Zhang Ping, Zhang Yuheng, Tian Mingliang
Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China.
Department of Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Phys Rev Lett. 2017 Jun 23;118(25):256601. doi: 10.1103/PhysRevLett.118.256601.
While pyrite-type PtBi_{2} with a face-centered cubic structure has been predicted to be a three-dimensional (3D) Dirac semimetal, experimental study of its physical properties remains absent. Here we report the angular-dependent magnetoresistance measurements of a PtBi_{2} single crystal under high magnetic fields. We observed extremely large unsaturated magnetoresistance (XMR) up to (11.2×10^{6})% at T=1.8 K in a magnetic field of 33 T, which is comparable to the previously reported Dirac materials, such as WTe_{2}, LaSb, and NbP. The crystals exhibit an ultrahigh mobility and significant Shubnikov-de Hass quantum oscillations with a nontrivial Berry phase. The analysis of Hall resistivity indicates that the XMR can be ascribed to the nearly compensated electron and hole. Our experimental results associated with the ab initio calculations suggest that pyrite PtBi_{2} is a topological semimetal candidate that might provide a platform for exploring topological materials with XMR in noble metal alloys.
虽然具有面心立方结构的黄铁矿型PtBi₂已被预测为三维（3D）狄拉克半金属，但其物理性质的实验研究仍然缺乏。在此，我们报告了在高磁场下对PtBi₂单晶进行的角度相关磁阻测量。我们在33 T磁场中于T = 1.8 K时观测到高达（11.2×10⁶）%的极大不饱和磁阻（XMR），这与先前报道的狄拉克材料如WTe₂、LaSb和NbP相当。这些晶体表现出超高迁移率和具有非平凡贝里相位的显著舒布尼科夫 - 德哈斯量子振荡。霍尔电阻率分析表明，XMR可归因于近乎补偿的电子和空穴。我们的实验结果与从头算计算相结合表明，黄铁矿型PtBi₂是一种拓扑半金属候选材料，可能为探索贵金属合金中具有XMR的拓扑材料提供一个平台。
