Band Engineering in Artificial Two-Dimensional Superlattice via Patterned Dielectric Substrates

Moiré superlattices of two-dimensional (2D) materials have been a remarkable platform for engineering flat bands and studying their emergent quantum states. However, in moiré superlattices, the band structure and physical properties are limited by the intrinsic moiré potential, which is determined by the twist angle and material selection, leading to the lack of in-situ versatile tunability. Moreover, the lattice symmetry is restricted by the material structure and random strain distributions also hinder further exploration of exotic quantum states. Here, we demonstrate an artificial superlattice imprinted onto a 2D platform by patterning periodic nanostructures with a periodicity of around 40 nm on dielectric substrates. By in-situ tuning of the superlattice potential using an electric field, we realize a spatially periodic potential landscape which is felt by the active material. We use optical spectroscopy to reveal the band modulation of the target material due to the periodic superlattice potential. Our work builds towards the realization of controlled engineering of the band structure in 2D materials by designing the superlattice periodicity and symmetries, paving the way for deeper exploration of exotic quantum phases.