Nodeless Hybridization as Proof of Trivial Topology in Samarium Hexaboride

Abstract

Calculations unanimously predict samarium hexaboride to be a topological Kondo insulator, the first topological insulator driven by strong electron correlation. As of today it appears also experimentally established as the only representative of this material class. Here, we investigate the three-dimensional band structure of SmB$_6$ and show that it is incompatible with a topological Kondo insulator which must have hybridization nodes at high-symmetry points. In addition we clarify the remaining questions concerning the nature of the surface states with new data. We address consequences for the search for correlated topological insulators.