Xing Dong, Tong Bingbing, Pan Senyang, Wang Zezhi, Luo Jianlin, Zhang Jinglei, Zhang Cheng-Long
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2024 May 23;15(1):4407. doi: 10.1038/s41467-024-48761-9.
Topological flat bands - where the kinetic energy of electrons is quenched - provide a platform for investigating the topological properties of correlated systems. Here, we report the observation of a topological flat band formed by polar-distortion-assisted Rashba splitting in the three-dimensional Dirac material ZrTe. The polar distortion and resulting Rashba splitting on the band are directly detected by torque magnetometry and the anomalous Hall effect, respectively. The local symmetry breaking further flattens the band, on which we observe resistance oscillations beyond the quantum limit. These oscillations follow the temperature dependence of the Lifshitz-Kosevich formula but are evenly distributed in B instead of 1/B at high magnetic fields. Furthermore, the cyclotron mass gets anomalously enhanced about 10 times at fields ~ 20 T. Our results provide an intrinsic platform without invoking moiré or order-stacking engineering, which opens the door for studying topologically correlated phenomena beyond two dimensions.
拓扑平带——电子动能被淬灭的区域——为研究关联系统的拓扑性质提供了一个平台。在此，我们报告了在三维狄拉克材料ZrTe中通过极性畸变辅助的 Rashba 分裂形成拓扑平带的观测结果。极性畸变以及能带上由此产生的 Rashba 分裂分别通过转矩磁强计和反常霍尔效应直接检测到。局域对称性破缺进一步使能带变平，在该平带上我们观测到了超出量子极限的电阻振荡。这些振荡遵循 Lifshitz-Kosevich 公式的温度依赖性，但在高磁场下在磁场 B 中均匀分布，而不是在 1/B 中。此外，在约 20 T 的磁场下，回旋质量反常增强了约 10 倍。我们的结果提供了一个无需引入莫尔或有序堆叠工程的本征平台，这为研究超越二维的拓扑关联现象打开了大门。
