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Emergence of Tertiary Dirac Points in Graphene Moire Superlattices

TitleEmergence of Tertiary Dirac Points in Graphene Moire Superlattices
Publication TypeJournal Article
Year of Publication2017
AuthorsChen, Guorui, Sui Mengqiao, Wang Duoming, Wang Shuopei, Jung Jeil, Moon Pilkyung, Adam Shaffique, Watanabe Kenji, Taniguchi Takashi, Zhou Shuyun, Koshino Mikito, Zhang Guangyu, and Zhane Yuanbo
JournalNano Lett.
Volume17
Pagination3576–3581
Date Published06/2017
ISSN1530-6984
Keywordselectrons, fermions, field-effect transistors, gaps, graphene, graphene superlattice, heterostructures, hexagonal boron-nitride, mobility, Moire pattern, scanning-tunneling-microscopy, tertialy Dirac point Landau level
Abstract

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 a moire superlattice that fundamentally modifies graphenes band structure and gives rise to secondary Dirac points (SDPs). Here we find that the formation of a moire 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 Kekule superstructure on top of the moire superlattice under appropriate carrier doping and magnetic fields.

DOI10.1021/acs.nanolett.7b00735

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