English

Moir\'e band model and band gaps of graphene on hexagonal boron nitride

Mesoscale and Nanoscale Physics 2017-09-06 v1

Abstract

Nearly aligned graphene on hexagonal boron nitride (G/BN) can be accurately modeled by a Dirac Hamiltonian perturbed by smoothly varying moir\'e pattern pseudospin fields. Here, we present the moir\'e-band model of G/BN for arbitrary small twist angles under a framework that combines symmetry considerations with input from ab-initio calculations. Our analysis of the band gaps at the primary and secondary Dirac points highlights the role of inversion symmetry breaking contributions of the moir\'e patterns, leading to primary Dirac point gaps when the moir\'e strains give rise to a finite average mass, and to secondary gaps when the moir\'e pseudospin components are mixed appropriately. The pseudomagnetic strain fields which can reach values of up to \sim40 Tesla near symmetry points in the moir\'e cell stem almost entirely from virtual hopping and dominate over the contributions arising from bond length distortions due to the moir\'e strains.

Keywords

Cite

@article{arxiv.1706.06016,
  title  = {Moir\'e band model and band gaps of graphene on hexagonal boron nitride},
  author = {Jeil Jung and Evan Laksono and Ashley M. DaSilva and Allan H. MacDonald and Marcin Mucha-Kruczyński and Shaffique Adam},
  journal= {arXiv preprint arXiv:1706.06016},
  year   = {2017}
}

Comments

14 pages, 8 figures, 3 tables