Quasiparticle Interference Evidence of the Topological Fermi Arc States in Chiral Fermionic Semimetal CoSi
Abstract
Chiral fermions in solid state feature "Fermi arc" states, connecting the surface projections of the bulk chiral nodes. The surface Fermi arc is a signature of nontrivial bulk topology. Unconventional chiral fermions with an extensive Fermi arc traversing the whole Brillouin zone have been theoretically proposed in CoSi. Here, we use scanning tunneling microscopy / spectroscopy to investigate quasiparticle interference at various terminations of a CoSi single crystal. The observed surface states exhibit chiral fermion-originated characteristics. These reside on (001) and (011) but not (111) surfaces with pi-rotation symmetry, spiral with energy, and disperse in a wide energy range from ~-200 to ~+400 mV. Owing to the high-energy and high-space resolution, a spin-orbit coupling-induced splitting of up to ~80 mV is identified. Our observations are corroborated by density functional theory and provide strong evidence that CoSi hosts the unconventional chiral fermions and the extensive Fermi arc states.
Keywords
Cite
@article{arxiv.2002.08647,
title = {Quasiparticle Interference Evidence of the Topological Fermi Arc States in Chiral Fermionic Semimetal CoSi},
author = {Qian-Qian Yuan and Liqin Zhou and Zhi-Cheng Rao and Shangjie Tian and Wei-Min Zhao and Cheng-Long Xue and Yixuan Liu and Tiantian Zhang and Cen-Yao Tang and Zhi-Qiang Shi and Zhen-Yu Jia and Hongming Weng and Hong Ding and Yu-Jie Sun and Hechang Lei and Shao-Chun Li},
journal= {arXiv preprint arXiv:2002.08647},
year = {2020}
}
Comments
20 pages, 4 figures