Patterned Dielectric Superlattices on van der Waals 2D Materials

Patterned Dielectric Superlattices provide a powerful route towards modifying electron bands in 2D materials through external electric fields. We pattern dielectric layers in our devices using e-beam lithography to achieve lattice wavelengths as small as 35nm while maintaining high device mobility. Using this technique, we have realized clear Brillouin zone folding in graphene on boron nitride systems as well as fully developed Hofstadter fractal quantization of unmatched quality in any system with a fabricated superlattice. We present transport data from graphene systems under both triangular and square superlattice potentials, which exhibit fractal spectra under magnetic field unique to those specific lattice geometries. Additionally, we can tune the superlattice potential strength by varying relevant gating voltages, and even turn off the superlattice altogether. We further present our efforts in extending PDSLs to a wider variety of van der Waals materials and measurement techniques.