Diverse Fermi-arc connectivity in the ferromagnetic Weyl semimetal Co3Sn2S2


  Pranab Kumar Nag [1]  ,  Noam Morali [1]  ,  Rajib Batabyal [1]  ,  Enke Liu [2,3]  ,  Qiunan Xu [2]  ,  Yan Sun [2]  ,  Binghai Yan [1]  ,  Claudia Felser [2]  ,  Nurit Avraham [1]  ,  Haim Beidenkopf [1]  
[1] Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
[2] Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
[3] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

Topological “Fermi-arc” states exist on certain surfaces of Weyl semimetals. They connect the surface projection of the bulk Weyl nodes. However, the actual connectivity among them remains ambiguous in the presence of multiple pairs of surface projected Weyl nodes. We use Fourier-transform scanning tunneling spectroscopy to verify the classification of the ferromagnetic Co3Sn2S2 as a magnetic Weyl semimetal as well as its time reversal broken origin. By studying three different surface terminations we show that both the Fermi-arc connectivity as well as the Fermi-arc contour in Co3Sn2Svary with the different surface potential. While on the Sn surface we find intra-Brillouin zone connectivity, on the Co surface the Fermi arcs connect Weyl nodes across the Brillouin zone edge. On the S termination the Fermi–arcs hybridize with non-topological bulk and thus their connectivity remain obscured.