Investigation of the magnetic Weyl semimetal candidate Co₃Sn₂S₂ by ARPES.

Topological phases in magnetic materials are a topic of current interest in the community. Recently, the kagome-lattice ferromagnet Co₃Sn₂S₂ was predicted to be a Weyl semimetal, while transport showed an exceptionally large anomalous Hall angle. Motivated by these exciting results, we use synchrotron ARPES to study single crystal Co₃Sn₂S₂. We observe a strong photon energy dependence consistent with out-of-plane k_z dispersion, even at moderate VUV photon energies. We compare our ARPES results with DFT and find a general match, with typical disagreement of ~ 0.1 eV. To address this disagreement, we perform muon/neutron scattering on Co₃Sn₂S₂ to better understand the magnetic state experimentally. We comment on progress using our muon/neutron results to match DFT to ARPES and evaluating possible changes in the predicted Weyl phase and other topological indices. Our results suggest that the search for topological magnets might benefit from an iterative approach building on muon/neutron measurements of the magnetic state, DFT and ARPES.