Metallic chemical potentials in an insulating topological state*

Controlling the charge density inside an insulator via the chemical potential is a cornerstone of modern electronics, enabling electrical conductivity of semiconductors and the emergence of fascinating new properties linked with electronic correlations. The compound SmB₆ has recently drawn widespread attention as the first insulator to feature both strong electronic correlations and topological quantum order, potentially hosting new phenomenologies as charge density is modified. However, chemical potential has not been experimentally controlled in studies to date of its electronic structure. In this talk I will present an angle-resolved photoemission spectromicroscopy (μ-ARPES) study of SmB₆, using the natural inhomogeneity of sample surfaces to create the analogue of a multi-dimensional doping series. I will discuss how we determine the role of correlations by observing interdependencies between topologically ordered electronic states and the chemical potential, and explain the effect of doping and quantum coherence in the electron system. Overall, this talk will set up the stage for a holistic understanding of the interplay between strong correlations and topological features in SmB₆.