Realization of correlated and topological electronic states in crystalline graphene

Electron-electron interactions can be significant in graphene with an ABC-stacking sequence. By developing innovative experimental techniques, we successfully fabricated high-quality ABC-stacked multilayer graphene and observed a correlated insulating state at charge neutrality, beginning with ABCA-tetralayer. Furthermore, by introducing proximity-induced spin-orbit coupling, at the charge neutrality point of ABCA-tetralayer, we achieved a topological Chern insulator with a layer-number-dependent Chern number of four.