Strain-induced Evolution of Electronic Band Structures in a Twisted   Graphene Bilayer
  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. 
Wei Yan, Wen-Yu He, Zhao-Dong Chu, Mengxi Liu, Lan Meng, Rui-Fen Dou,   Yanfeng Zhang, Zhongfan Liu, Jia-Cai Nie, and Lin He
cond-mat.mes-hall cond-mat.mtrl-sci