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The interplay of magnetism and strongly correlated topology is expected to generate exotic quantum phenomena. SmB₆ is a leading platform, as it was recently shown to host heavy Dirac surface states that form within a screened Kondo lattice [1]. In conventional heavy fermion materials, it is well known that local magnetic structure is nucleated by Kondo holes–substitutions on the f-electron contributing lattice. If the same mechanism exists in the topological counterparts to these systems, Kondo holes would provide a local gauge of the impact of magnetism on the emergent heavy Dirac fermions. However, current experimental techniques to image the microscopic signature of a Kondo hole are challenging, and require tracking the complex heavy fermion band structure. Here, we introduce electrochemical potential imaging spectroscopy to directly visualize the impact of Kondo holes from the liberation of screening electrons around them. In SmB₆, we discover that Sm-site defects create Kondo holes that locally break topological protection, allowing backscattering of heavy Dirac fermions.

[1] Pirie et al., Nat. Phys., in press (2019)