Observation of termination-dependent topological connectivity in a magnetic Weyl kagome-lattice

Engineering surfaces and interfaces of materials promises great potential in the field of heterostructures and quantum matter designer, with the opportunity of driving new many-body phases that are not present in the bulk compounds. Here, we focus on recently-synthesized magnetic Weyl kagome systems and show that the way the Fermi arcs connect their Weyl points depends on the type of surface termination. In particular, we reveal how the surface environment naturally created by the crystal cleavage planes, can modulate the topological bulk-to-surface connectivity. By a combination of (nano-)angleresolved photoelectron spectroscopy and first-principles calculations, we probe the energy-momentum spectra and the Fermi surfaces of Co3Sn2S2 for different surface terminations and show the existence of topological features directly depending on the top-layer electronic environment. Our work helps to define a route to control bulk-derived topological properties by means of surface electrostatic potentials, creating a realistic and reliable methodology to use Weyl kagome metals in responsive magnetic spintronics.