Strain-induced Evolution of Electronic Band Structures in a Twisted Graphene Bilayer

2012/06/30 by Wei Yan, Wen-Yu He, Zhao-Dong Chu +7 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.mtrl-sci

paper · pdf · doi:10.1038/ncomms3159

published as Nature Communications 4, 2159 (2013) · 4 figures

arxiv created 2013/03/14 · arxiv updated 2015/06/05

Abstract

Here we study the evolution of local electronic properties of a twisted graphene bilayer induced by a strain and a high curvature. The strain and curvature strongly affect the local band structures of the twisted graphene bilayer; the energy difference of the two low-energy van Hove singularities decreases with increasing the lattice deformations and the states condensed into well-defined pseudo-Landau levels, which mimic the quantization of massive Dirac fermions in a magnetic field of about 100 T, along a graphene wrinkle. The joint effect of strain and out-of-plane distortion in the graphene wrinkle also results in a valley polarization with a significant gap, i.e., the eight-fold degenerate Landau level at the charge neutrality point is splitted into two four-fold degenerate quartets polarized on each layer. These results suggest that strained graphene bilayer could be an ideal platform to realize the high-temperature zero-field quantum valley Hall effect.

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