Details

Autor(en) / Beteiligte

• Yuan, Qian-Qian
• Zhou, Liqin
• Rao, Zhi-Cheng
• Tian, Shangjie
• Zhao, Wei-Min
• Xue, Cheng-Long
• Liu, Yixuan
• Zhang, Tiantian
• Tang, Cen-Yao
• Shi, Zhi-Qiang
• Jia, Zhen-Yu
• Weng, Hongming
• Ding, Hong
• Sun, Yu-Jie
• Lei, Hechang
• Li, Shao-Chun

Titel

Quasiparticle interference evidence of the topological Fermi arc states in chiral fermionic semimetal CoSi

Ist Teil von

• Science advances, 2019-12, Vol.5 (12), p.eaaw9485-eaaw9485

Ort / Verlag

United States: American Association for the Advancement of Science

Erscheinungsjahr

2019

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• 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 p-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.