Assessing Nontrivial Topology in Weyl Semimetals by Dichroic Photoemission br

The electronic structure of Weyl semimetals features Berry flux monopoles in the bulk and Fermi arcs atthe surface. While angle-resolved photoelectron spectroscopy (ARPES) is successfully used to map thebulk and surface bands, it remains a challenge to explicitly resolve and pinpoint these topological features.Here we combine state-of-the-art photoemission theory and experiments over a wide range of excitationenergies for the Weyl semimetals TaAs and TaP. Our results show that simple surface-band-countingschemes, proposed previously to identify nonzero Chern numbers, are ambiguous due to pronouncedmomentum-dependent spectral weight variations and the pronounced surface-bulk hybridization. Instead,our findings indicate that dichroic ARPES provides an improved approach to identify Fermi arcs butrequires an accurate description of the photoelectron final state