Lu Qiangsheng, Reddy P V Sreenivasa, Jeon Hoyeon, Mazza Alessandro R, Brahlek Matthew, Wu Weikang, Yang Shengyuan A, Cook Jacob, Conner Clayton, Zhang Xiaoqian, Chakraborty Amarnath, Yao Yueh-Ting, Tien Hung-Ju, Tseng Chun-Han, Yang Po-Yuan, Lien Shang-Wei, Lin Hsin, Chiang Tai-Chang, Vignale Giovanni, Li An-Ping, Chang Tay-Rong, Moore Rob G, Bian Guang
Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA.
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
Nat Commun. 2024 Jul 17;15(1):6001. doi: 10.1038/s41467-024-50329-6.
A two-dimensional (2D) Weyl semimetal, akin to a spinful variant of graphene, represents a topological matter characterized by Weyl fermion-like quasiparticles in low dimensions. The spinful linear band structure in two dimensions gives rise to distinctive topological properties, accompanied by the emergence of Fermi string edge states. We report the experimental realization of a 2D Weyl semimetal, bismuthene monolayer grown on SnS(Se) substrates. Using spin and angle-resolved photoemission and scanning tunneling spectroscopies, we directly observe spin-polarized Weyl cones, Weyl nodes, and Fermi strings, providing consistent evidence of their inherent topological characteristics. Our work opens the door for the experimental study of Weyl fermions in low-dimensional materials.
二维（2D）外尔半金属类似于具有自旋的石墨烯变体，是一种拓扑物质，其特征在于低维中类似外尔费米子的准粒子。二维中具有自旋的线性能带结构产生了独特的拓扑性质，并伴随着费米弦边缘态的出现。我们报告了二维外尔半金属——生长在SnS（Se）衬底上的单层铋烯的实验实现。利用自旋和角分辨光电子能谱以及扫描隧道谱，我们直接观测到了自旋极化的外尔锥、外尔点和费米弦，为它们固有的拓扑特性提供了一致的证据。我们的工作为低维材料中外尔费米子的实验研究打开了大门。
