Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene
Name
PhysRevLett.117.116804.pdf
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1.15 MB
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Adobe PDF
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Author(s)
Fang, S.
Sanchez-Yamagishi, J. D.
Watanabe, K.
Taniguchi, T.
Kaxiras, E.
Cao, Y.
Fatemi, Valla
Luo, J. Y.
Jarillo-Herrero, Pablo
Date Issued
September 2016
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Cao, Y. et al. “Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene.” Physical Review Letters 117.11 (2016): n. pag. © 2016 American Physical Society
Version
Final published version
Abstract
Twisted bilayer graphene (TBLG) is one of the simplest van der Waals heterostructures, yet it yields a complex electronic system with intricate interplay between moiré physics and interlayer hybridization effects. We report on electronic transport measurements of high mobility small angle TBLG devices showing clear evidence for insulating states at the superlattice band edges, with thermal activation gaps several times larger than theoretically predicted. Moreover, Shubnikov–de Haas oscillations and tight binding calculations reveal that the band structure consists of two intersecting Fermi contours whose crossing points are effectively unhybridized. We attribute this to exponentially suppressed interlayer hopping amplitudes for momentum transfers larger than the moiré wave vector.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.117.116804
