Moiré patterns are well-known phenomena in art, textiles and mathematics, which originate from the overlay of two periodic patterns. Intriguingly, atomically thin materials can be stacked on top of each other such that a new periodic pattern can emerge: the moiré superlattice. This can result in a dramatic modification of the electronic and optical properties of twisted 2D materials, compared to those of a single layer. The moiré superlattice can give rise to a plethora of interesting phenomena such as topological bands and many-body phases like superconductivity and magnetism.
In this talk, we give an overview of the nano-optical properties of 2D material superlattices, obtained by twisting or nanostructuring. Nanoscale optical techniques such as near-field optical microscopy reveal with nanometer spatial resolution unique observations of topological domain wall boundaries, hyperbolic phononic lattices, and interband collective modes in charge neutral TBG near the magic angle. The freedom to engineer these so-called optical and electronic quantum metamaterials  is expected to expose a myriad of unexpected phenomena.
Coffee and pastries at 11h00.