The electronic structure of a crystalline solid is largely determined by its lattice structure. Recent advances in van der Waals solids, artificial crystals with controlled stacking of two-dimensional (2D) atomic films, have enabled the creation of materials with novel electronic structures. In particular, stacking graphene on hexagonal boron nitride (hBN) introduces moir\'e superlattice that fundamentally modifies graphene's band structure and gives rise to secondary Dirac points (SDPs). Here we find that the formation of a moir\'e superlattice in graphene on hBN yields new, unexpected consequences: a set of tertiary Dirac points (TDPs) emerge, which give rise to additional sets of Landau levels when the sample is subjected to an external magnetic field. Our observations hint at the formation of a hidden Kekul\'e superstructure on top of the moir\'e superlattice under appropriate carrier doping and magnetic fields.
@article{arxiv.1702.03107,
title = {Emergence of Tertiary Dirac Points in Graphene Moir\'e Superlattices},
author = {Guorui Chen and Mengqiao Sui and Duoming Wang and Shuopei Wang and Jeil Jung and Pilkyung Moon and Shaffique Adam and Kenji Watanabe and Takashi Taniguchi and Shuyun Zhou and Mikito Koshino and Guangyu Zhang and Yuanbo Zhang},
journal= {arXiv preprint arXiv:1702.03107},
year = {2017}
}