Observation of 1D Fermi arc states in Weyl semimetal TaAs

作     者：Xiaohu Zheng Qiangqiang Gu Yiyuan Liu Bingbing Tong Jian-Feng Zhang Chi Zhang Shuang Jia Ji Feng Rui-Rui Du Xiaohu Zheng;Qiangqiang Gu;Yiyuan Liu;Bingbing Tong;Jian-Feng Zhang;Chi Zhang;Shuang Jia;Ji Feng;Rui-Rui Du

作者机构：International Center for Quantum MaterialsSchool of PhysicsPeking University Collaborative Innovation Center of Quantum Matter State Key Laboratory of Superlattices and MicrostructuresInstitute of SemiconductorsChinese Academy of Sciences CAS Center for Excellence in Topological Quantum ComputationUniversity of Chinese Academy of Sciences Beijing Academy of Quantum Information Sciences 

出 版 物：《National Science Review》 (国家科学评论(英文版))

年 卷 期：2022年第9卷第8期

页      面：62-70页

核心收录：

学科分类：07[理学] 070201[理学-理论物理] 0703[理学-化学] 0701[理学-数学] 0702[理学-物理学] 

基　　金：supported by the National Key Research and Development Program of China (2016YFA0301004,2017YFA0303301, 2018YFA0305601 and 2019YFA0308400) the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB28000000) the National Natural Science Foundation of China (11725415, 11921005 and 11934001) the National Natural Science Foundation of China Young Scientists Program (11704010) 

主　　题：Weyl semimetals Fermi arc edge states chiral Weyl points TaAs scanning tunneling microscopy/spectroscopy 

摘      要：Fermi arcs on Weyl semimetals exhibit many exotic quantum phenomena. Usually found on atomically flat surfaces with approximate translation symmetry, Fermi arcs are rooted in the peculiar topology of bulk Bloch bands of 3D crystals. The fundamental question of whether a 1D Fermi arc can be probed remains unanswered. Such an answer could significantly broaden potential applications of Weyl semimetals. Here,we report a direct observation of robust edge states on atomic-scale ledges in TaAs using low-temperature scanning tunneling microscopy/spectroscopy. Spectroscopic signatures and theoretical calculations reveal that the 1D Fermi arcs arise from the chiral Weyl points of bulk crystals. The crossover from 2D Fermi arcs to eventual complete localization on 1D edges was arrested experimentally on a sequence of surfaces. Our results demonstrate extreme robustness of the bulk-boundary correspondence, which offers topological protection for Fermi arcs, even in cases in which the boundaries are at the atomic-scale. The persistent 1D Fermi arcs can be profitably exploited in miniaturized quantum devices.