The use of relative twist angle between adjacent atomic layers in a van der Waals heterostructure, has emerged as a new degree of freedom to tune electronic and optoelectronic properties of devices based on 2D materials. Using ABA-stacked trilayer (TLG) graphene as the model system, we show that, contrary to conventional wisdom, the band structures of 2D materials are systematically tunable depending on their relative alignment angle between hexagonal BN (hBN), even at very large twist angles. Moreover, addition or removal of the hBN substrate results in an inversion of the K and K' valley in TLG's lowest Landau level (LL). Our work illustrates the critical role played by substrates in van der Waals heterostructures and opens the door towards band structure modification and valley control via substrate and twist angle engineering.
@article{arxiv.1803.03679,
title = {Twist Angle-Dependent Bands and Valley Inversion in 2D Materials/hBN Heterostructures},
author = {Shi Che and Petr Stepanov and Supeng Ge and Yongjin Lee and Kevin Myhro and Yanmeng Shi and Ruoyu Chen and Ziqi Pi and Cheng Pan and Bin Cheng and Takashi Taniguchi and Kenji Watanabe and Marc Bockrath and Yafis Barlas and Roger Lake and Chun Ning Lau},
journal= {arXiv preprint arXiv:1803.03679},
year = {2021}
}