Meron and Chiral Kondo lattices in topological insulators and heterostructures

In this presentation, we present two topological phenomena emerging from the interplay of strong spin-orbit coupling and correlation effects. Firstly, I will discuss the fate of the surface Dirac cone of a three-dimensional topological insulator subject to a superlattice potential. Due to the topological nature of the bulk, surface band gaps cannot open; instead, prominent van Hove singularities emerge around charge neutrality. The latter combined with the strong spin-orbit coupling and Coulomb repulsion, give rise to a topological meron lattice spin texture. Numerical calculations are supported by a Ginzburg-Landau theory that we employed to classify the different magnetic orders of the surface Dirac modes. Shifting gears, the investigation then turns to transition metal dichalcogenides heterobilayer systems. This highly tunable platform enables unprecedent control over the ground state, opening the door to the synthetic realization of an orbital selective Mott transition. Here, non-local spin exchange processes lead to a chiral Kondo coupling, adding a unique twist to heavy fermion physics. We discuss the distinctive features of this state, including a strong dependence of the Kondo temperature on electron density, an anomalous Hall effect induced by chiral exchange, and the emergence of a topological spin-Hall Kondo insulator at integer filling. Finally, we present a purely repulsive mechanism leading to superconductivity in the small Fermi surface regime where the local moments are magnetically ordered. The implications of these findings for future experiments are discussed.