Criteria for Directly Detecting Topological Fermi Arcs in Weyl Semimetals

Ilya Belopolski, Su Yang Xu, Daniel S. Sanchez, Guoqing Chang, Cheng Guo, Madhab Neupane, Hao Zheng, Chi Cheng Lee, Shin Ming Huang, Guang Bian, Nasser Alidoust, Tay Rong Chang, Baokai Wang, Xiao Zhang, Arun Bansil, Horng Tay Jeng, Hsin Lin, Shuang Jia, M. Zahid Hasan

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132 Scopus citations


The recent discovery of the first Weyl semimetal in TaAs provides the first observation of a Weyl fermion in nature and demonstrates a novel type of anomalous surface state, the Fermi arc. Like topological insulators, the bulk topological invariants of a Weyl semimetal are uniquely fixed by the surface states of a bulk sample. Here we present a set of distinct conditions, accessible by angle-resolved photoemission spectroscopy (ARPES), each of which demonstrates topological Fermi arcs in a surface state band structure, with minimal reliance on calculation. We apply these results to TaAs and NbP. For the first time, we rigorously demonstrate a nonzero Chern number in TaAs by counting chiral edge modes on a closed loop. We further show that it is unreasonable to directly observe Fermi arcs in NbP by ARPES within available experimental resolution and spectral linewidth. Our results are general and apply to any new material to demonstrate a Weyl semimetal.

Original languageEnglish (US)
Article number066802
JournalPhysical review letters
Issue number6
StatePublished - Feb 10 2016

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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