Hofstadter Butterfly and Many-Body Effects in Epitaxial Graphene Superlattice
journal contributionposted on 07.03.2016, 00:00 by Wei Yang, Xiaobo Lu, Guorui Chen, Shuang Wu, Guibai Xie, Meng Cheng, Duoming Wang, Rong Yang, Dongxia Shi, Kenji Watanabe, Takashi Taniguchi, Christophe Voisin, Bernard Plaçais, Yuanbo Zhang, Guangyu Zhang
Graphene placed on hexagonal boron nitride (h-BN) has received a wide range of interest due to the improved electrical performance and rich physics from the interface, especially the emergence of superlattice Dirac points as well as Hofstadter butterfly in high magnetic field. Instead of transferring graphene onto h-BN, epitaxial growth of graphene directly on a single-crystal h-BN provides an alternative and promising way to study these interesting superlattice effects due to their precise lattice alignment. Here we report an electrical transport study on epitaxial graphene superlattice on h-BN with a period of ∼15.6 nm. The epitaxial graphene superlattice is clean, intrinsic, and of high quality with a carrier mobility of ∼27 000 cm2 V–1 s–1, which enables the observation of Hofstadter butterfly features originated from the superlattice at a magnetic field as low as 6.4 T. A metal–insulator transition and magnetic field dependent Fermi velocity were also observed, suggesting prominent electron–electron interaction-induced many-body effects.