SmB6, a well-known Kondo insulator, has been proposed to be an ideal topological insulator with states of topological character located in a clean, bulk electronic gap, namely the Kondo hybridization gap. Seeing as the Kondo gap arises from many body electronic correlations, this would place SmB6 at the head of a new material class: topological Kondo insulators. Here, for the first time, we show that the k-space characteristics of the Kondo hybridization process is the key to unravelling the origin of the two types of metallic states experimentally observed by ARPES in the electronic band structure of SmB6(001). One group of these states is essentially of bulk origin, and cuts the Fermi level due to the position of the chemical potential 20 meV above the lowest lying 5d-4f hybridization zone. The other metallic state is more enigmatic, being weak in intensity, but represents a good candidate for a topological surface state. However, before this claim can be substantiated by an unequivocal measurement of its massless dispersion relation, our data raises the bar in terms of the ARPES resolution required, as we show there to be a strong renormalization of the hybridization gaps by a factor 2-3 compared to theory, following from the knowledge of the true position of the chemical potential and a careful comparison with the predictions from recent LDA+Gutzwiller calculations. All in all, these key pieces of evidence act as triangulation markers, providing a detailed description of the electronic landscape in SmB6, pointing the way for future, ultrahigh resolution ARPES experiments to achieve a direct measurement of the Dirac cones in the first topological Kondo insulator. * e.frantzeskakis@uva.nl † m.s.golden@uva.nl

Determining the most appropriate way to represent the relationships between bacterial isolates is complicated by the differing rates of recombination within species. In many cases, a bifurcating tree can be positively misleading. The recently described program eBURST can be used with multilocus data to define groups or clonal complexes of related isolates derived from a common ancestor, the patterns of descent linking them together, and the ancestral genotype. eBURST has recently been extensively updated to include additional tools for exploring the relationships between isolates. We discuss the advantages of this approach and describe its use to explore patterns of descent within clonal complexes identified using multilocus sequence typing.

No abstract