Interaction-driven sub-gap resonance in the topological Kondo insulator SmB6

Samarium hexaboride (SmB6) is a strongly correlated Kondo Insulator with a non-trivial band-structure topology. I will discuss recent neutron scattering experiments and analysis that expose a 14 meV resonant mode in SmB6 and relate it to the low energy insulating band structure. Repeating outside the first Brillouin zone, the mode is coherent with a 5$d$-like magnetic form factor. I will discuss how band inversion can be inferred from neutron scattering and show that a perturbative slave boson treatment of a hybridized 2 species ($d$/$f$) band structure within an Anderson model can produce a spin exciton with the observed characteristics. This analysis provides a detailed physical picture of how the SmB6 band topology arises from strong electron interactions, and accounts for the 14 meV resonant mode as a magnetically active exciton.