Massive Dirac Fermions and Hofstadter Butterfly in a van der Waals Heterostructure
Author(s)Yankowitz, M.; LeRoy, Brian J.; Watanabe, K.; Taniguchi, T.; Moon, P.; Koshino, M.; Hunt, Benjamin Matthew; Sanchez, Javier Daniel; Young, Andrea Franchini; Jarillo-Herrero, Pablo; Ashoori, Raymond; ... Show more Show less
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van der Waals heterostructures constitute a new class of artificial materials formed by stacking atomically thin planar crystals. We demonstrated band structure engineering in a van der Waals heterostructure composed of a monolayer graphene flake coupled to a rotationally aligned hexagonal boron nitride substrate. The spatially varying interlayer atomic registry results in both a local breaking of the carbon sublattice symmetry and a long-range moiré superlattice potential in the graphene. In our samples, this interplay between short- and long-wavelength effects resulted in a band structure described by isolated superlattice minibands and an unexpectedly large band gap at charge neutrality. This picture is confirmed by our observation of fractional quantum Hall states at ±5/3 filling and features associated with the Hofstadter butterfly at ultrahigh magnetic fields.
DepartmentMassachusetts Institute of Technology. Department of Physics
American Association for the Advancement of Science (AAAS)
Hunt, B., J. D. Sanchez-Yamagishi, A. F. Young, M. Yankowitz, B. J. LeRoy, K. Watanabe, T. Taniguchi, et al. “Massive Dirac Fermions and Hofstadter Butterfly in a van Der Waals Heterostructure.” Science 340, no. 6139 (June 21, 2013): 1427–1430.
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