Emergent phases often appear when the electronic kinetic energy is small compared to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional (2D) kagome lattice, including magnetic order, time-reversal symmetry breaking charge density wave, nematicity, and superconductivity. In this talk, I will present our recent efforts in experimentally exploring bulk materials hosting flat bands induced from the geometric frustration of the lattice. In particular, I will present three examples of topological flat bands including a magnetic kagome system, a pyrochlore system, and a switchable bipartite lattice that forms within a 2D van der Waals magnet.

Please contact phweb@ust.hk should you have questions about the talk.