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Nat Commun. 2014 Jul 18;5:4461. doi: 10.1038/ncomms5461.

Observation of an intrinsic bandgap and Landau level renormalization in graphene/boron-nitride heterostructures.

Author information

1
National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA.
2
Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
3
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
4
IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA.
5
1] Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA [2] Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

Abstract

Van der Waals heterostructures formed by assembling different two-dimensional atomic crystals into stacks can lead to many new phenomena and device functionalities. In particular, graphene/boron-nitride heterostructures have emerged as a very promising system for band engineering of graphene. However, the intrinsic value and origin of the bandgap in such heterostructures remain unresolved. Here we report the observation of an intrinsic bandgap in epitaxial graphene/boron-nitride heterostructures with zero crystallographic alignment angle. Magneto-optical spectroscopy provides a direct probe of the Landau level transitions in this system and reveals a bandgap of ~38 meV (440 K). Moreover, the Landau level transitions are characterized by effective Fermi velocities with a critical dependence on specific transitions and magnetic field. These findings highlight the important role of many-body interactions in determining the fundamental properties of graphene heterostructures.

PMID:
25034319
DOI:
10.1038/ncomms5461

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