Chirality-dependent topological states in twisted double bilayer graphene

The properties of van der Waals (vdW) crystals and heterostructures depend sensitively on their layer stacking configuration. The twist angle and lattice mismatch between constituent vdW sheets have been shown to be crucial parameters influencing the strongly correlated and topological states of matter in moiré materials. Here, we demonstrate a new approach for controlling these emergent states by altering the stacking chirality of the moiré structure. We study twisted double bilayer graphene (tDBG) in an AB-BA stacking configuration (i.e., with the component Bernal bilayers rotated by nearly 60°) and observe topological and symmetry-broken states that are absent in AB-AB stacked tDBG. Our results motivate future experiments in which the stacking chirality is employed as an important new degree of freedom for controlling the strongly correlated and topological phase diagram of other moiré materials.