Qiu Gang, Niu Chang, Wang Yixiu, Si Mengwei, Zhang Zhuocheng, Wu Wenzhuo, Ye Peide D
School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
Birck Nanotechnology Centre, Purdue University, West Lafayette, IN, USA.
Nat Nanotechnol. 2020 Jul;15(7):585-591. doi: 10.1038/s41565-020-0715-4. Epub 2020 Jun 29.
Dirac and Weyl nodal materials can host low-energy relativistic quasiparticles. Under strong magnetic fields, the topological properties of Dirac/Weyl materials can directly be observed through quantum Hall states. However, most Dirac/Weyl nodes generically exist in semimetals without exploitable band gaps due to their accidental band-crossing origin. Here, we report the first experimental observation of Weyl fermions in a semiconductor. Tellurene, the two-dimensional form of tellurium, possesses a chiral crystal structure which induces unconventional Weyl nodes with a hedgehog-like radial spin texture near the conduction band edge. We synthesize high-quality n-type tellurene by a hydrothermal method with subsequent dielectric doping and detect a topologically non-trivial π Berry phase in quantum Hall sequences. Our work expands the spectrum of Weyl matter into semiconductors and offers a new platform to design novel quantum devices by marrying the advantages of topological materials to versatile semiconductors.
狄拉克和外尔节线材料可以容纳低能相对论性准粒子。在强磁场下，狄拉克/外尔材料的拓扑性质可以通过量子霍尔态直接观测到。然而，由于其偶然的能带交叉起源，大多数狄拉克/外尔节线通常存在于没有可利用带隙的半金属中。在此，我们报告了在半导体中首次对外尔费米子进行的实验观测。碲烯，即碲的二维形式，具有手性晶体结构，在导带边缘附近诱导出具有刺猬状径向自旋纹理的非常规外尔节线。我们通过水热法并随后进行介电掺杂合成了高质量的n型碲烯，并在量子霍尔序列中检测到拓扑非平凡的π贝里相位。我们的工作将外尔物质的范围扩展到了半导体，并通过将拓扑材料的优势与通用半导体相结合，为设计新型量子器件提供了一个新平台。
