Session 5-2

Abstract

We present a theoretical study of lattice relaxation and electronic structures in twisted trilayer graphene and transition metal dichalcogenides (TMDs). In graphene, relaxation produces a patchwork of moiré-of-moiré domains, with electronic properties strongly dependent on stacking: helical trilayers host one-dimensional topological boundary states, while alternating trilayers yield distinct Chern insulating domains. In TMDs such as WSe₂, relaxation also forms domain structures, but the electronic states are governed by intralayer moiré potentials. Superposition of potentials from both outer layers on the middle layer doubles the effective depth, producing Kagome flat bands in helical stacks and deep triangular wells in alternating stacks. A perpendicular electric field can further switch layer polarization and tune interlayer hybridization. These results highlight trilayer stacking as a new route to engineer moiré physics beyond bilayer systems.