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.

Keywords

SuperlatticeCondensed matter physicsBilayer grapheneGrapheneHeterojunctionPhysicsFermi Gamma-ray Space TelescopeFermi levelElectronic band structureMaterials scienceElectronQuantum mechanics

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Publication Info

Year
2016
Type
article
Volume
117
Issue
11
Pages
116804-116804
Citations
407
Access
Closed

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Cite This

Yuan Cao, Jason Luo, Valla Fatemi et al. (2016). Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene. Physical Review Letters , 117 (11) , 116804-116804. https://doi.org/10.1103/physrevlett.117.116804

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DOI
10.1103/physrevlett.117.116804