Electrically tunable moiré hybridization in scalable twist-with-a-spacer structures

Moiré superlattices emerge from the interplay between interlayer hybridization and long-wavelength periodicity, both set by the twist angle between layers in direct contact. Here we show that moiré minibands and pronounced Brown-Zak oscillations persist even when twisted graphene layers are separated by an atomically thin spacer, such as a misaligned graphene monolayer. This twist-with-a-spacer architecture reduces interlayer coupling, such that moiré hybridization can be tuned with a modest displacement field without changing moiré periodicity, allowing us to disentangle the roles of those parameters in miniband formation. Importantly, the spacer suppresses atomic relaxation, enabling highly uniform, rigid superlattices at twist angles down to ~0.1 degree. This robustness allows twist-with-a-spacer structures to be grown directly by scalable chemical vapour deposition (CVD): devices fabricated from CVD-grown structures exhibit the same moiré physics phenomena as those assembled manually. Our work provides insights into the physics of moiré bandstructure formation and opens a route towards scalable moiré systems.