TOPOLOGY AND QUANTUM CRITICALITY IN KONDO INSULATORS (TopQuantum)
Quantum criticality has emerged as a key organizing principle in condensed matter. It is observed in systems as distinct as organic conductors, oxide interfaces, pnictide and cuprate superconductors, itinerant magnets, and heavy fermion metals. The latter have been most extensively investigated in this respect. Not only are the quantum critical fluctuations in these systems responsible for pronounced non-Fermi liquid behaviour and unconventional superconductivity but also does the analysis of the quantum critical properties reveal deep insight into the faith of the adjacent phases. Kondo insulators, the insulating sister compounds of heavy fermion metals, have received comparably little attention. This has changed since the recent claim that SmB6 is a topological Kondo insulator. Topological insulators, and in particular their strongly correlated “Kondo” versions, are of great fundamental interest as new phases of matter. In addition, their topologically protected conducting surface states might open new directions in electronic devices. TopQuantum aims at significantly advancing the understanding of the intriguing interplay between strong correlations, symmetry, and topology by driving carefully selected Kondo insulators with substitutions and/or pressure between different phases: insulating to metallic, paramagnetic to magnetic, topological to topologically trivial. The evolution of the physical properties across these transitions will be key to identify the nature of the accessed phases.