Dirac electrons in Moire superlattice: From two to three dimensions
C Hu and V Michaud-Rioux and XH Kong and H Guo, PHYSICAL REVIEW MATERIALS, 1, 061003 (2017).
Moire patterns in van derWaals (vdW) heterostructures bring novel physical effects to the materials. We report theoretical investigations of the Moire pattern formed by graphene (Gr) on hexagonal boron nitride (hBN). For both the two-dimensional (2D) flat-sheet and the freestanding three-dimensional (3D) wavelike film geometries, the behaviors of Dirac electrons are strongly modulated by the local high-symmetry stacking configurations of the Moire pattern. In the 2D flat sheet, the secondary Dirac cone (SDC) dispersion emerges due to the stacking-selected localization of SDC wave functions, while the original Dirac cone (ODC) gap is suppressed due to an overall effect of ODC wave functions. In the freestanding 3D wavelike Moire structure, we predict that a specific local stacking in the Moire superlattice is promoted at the expense of other local stackings, leading to an electronic structure more similar to that of the perfectly matching flat Gr/hBN than that of the flat- sheet 2D Moire pattern. To capture the overall picture of the Moire superlattice, supercells containing 12 322 atoms are simulated by first principles.
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