Deng Jialiang, Xia Bingyu, Ma Xiaochuan, Chen Haoqi, Shan Huan, Zhai Xiaofang, Li Bin, Zhao Aidi, Xu Yong, Duan Wenhui, Zhang Shou-Cheng, Wang Bing, Hou J G
Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, China.
State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
Nat Mater. 2018 Dec;17(12):1081-1086. doi: 10.1038/s41563-018-0203-5. Epub 2018 Nov 5.
Two-dimensional (2D) topological materials, including quantum spin/anomalous Hall insulators, have attracted intense research efforts owing to their promise for applications ranging from low-power electronics and high-performance thermoelectrics to fault-tolerant quantum computation. One key challenge is to fabricate topological materials with a large energy gap for room-temperature use. Stanene-the tin counterpart of graphene-is a promising material candidate distinguished by its tunable topological states and sizeable bandgap. Recent experiments have successfully fabricated stanene, but none of them have yet observed topological states. Here we demonstrate the growth of high-quality stanene on Cu(111) by low-temperature molecular beam epitaxy. Importantly, we discovered an unusually ultraflat stanene showing an in-plane s-p band inversion together with a spin-orbit-coupling-induced topological gap (~0.3 eV) at the Γ point, which represents a foremost group-IV ultraflat graphene-like material displaying topological features in experiment. The finding of ultraflat stanene opens opportunities for exploring two-dimensional topological physics and device applications.
二维（2D）拓扑材料，包括量子自旋/反常霍尔绝缘体，因其在从低功耗电子学、高性能热电器件到容错量子计算等一系列应用中的潜力而吸引了广泛的研究。一个关键挑战是制造出具有大能隙以供室温使用的拓扑材料。锡烯——石墨烯的锡类似物——是一种很有前景的材料候选物，其特点是具有可调节的拓扑态和可观的带隙。最近的实验已成功制备出锡烯，但尚未有实验观测到拓扑态。在此，我们通过低温分子束外延展示了在Cu(111)上高质量锡烯的生长。重要的是，我们发现了一种异常超平坦的锡烯，其在平面内呈现s - p带反转，并且在Γ点处存在自旋轨道耦合诱导的拓扑能隙（约0.3 eV），这是实验中首个呈现拓扑特征的第IV族类石墨烯超平坦材料。超平坦锡烯的这一发现为探索二维拓扑物理和器件应用开辟了机会。
