Emergence of superlattice Dirac points in graphene on hexagonal boron nitride
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Jarillo-Herrero_Emergence of.pdf
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Author(s)
Yankowitz, Matthew
Xue, Jiamin
Cormode, Daniel
Sanchez-Yamagishi, Javier
Watanabe, K.
Taniguchi, T.
Jarillo-Herrero, Pablo
Jacquod, Philippe
LeRoy, Brian J.
Date Issued
March 2012
Journal
Nature Physics
Publisher
Nature Publishing Group
Citation
Yankowitz, Matthew et al. “Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron Nitride.” Nature Physics 8.5 (2012): 382–386. Web.
Version
Author's final manuscript
Abstract
The Schrödinger equation dictates that the propagation of nearly free electrons through a weak periodic potential results in the opening of bandgaps near points of the reciprocal lattice known as Brillouin zone boundaries1. However, in the case of massless Dirac fermions, it has been predicted that the chirality of the charge carriers prevents the opening of a bandgap and instead new Dirac points appear in the electronic structure of the material. Graphene on hexagonal boron nitride exhibits a rotation-dependent moiré pattern. Here, we show experimentally and theoretically that this moiré pattern acts as a weak periodic potential and thereby leads to the emergence of a new set of Dirac points at an energy determined by its wavelength. The new massless Dirac fermions generated at these superlattice Dirac points are characterized by a significantly reduced Fermi velocity. Furthermore, the local density of states near these Dirac cones exhibits hexagonal modulation due to the influence of the periodic potential.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/nphys2272
