Commensurate and incommensurate double moire interference in graphene encapsulated by hexagonal boron nitride

Abstract

Interference of double moire patterns of graphene (G) encapsulated by hexagonal boron nitride (BN) can alter the electronic structure features near the primary/secondary Dirac points and the electron-hole symmetry introduced by a single G/BN moire pattern depending on the relative stacking arrangements of the top/bottom BN layers. We show that strong interference effects are found in nearly aligned BN/G/BN and BN/G/NB and obtain the evolution of the associated density of states as a function of moire superlattice twist angles. For equal moire periods and commensurate patterns with Δφ = 0° modulo 60° moire angle differences the patterns can add up constructively leading to large pseudogaps of about ∼ 50 meV on the hole side or cancel out destructively depending on their relative sliding, e.g. partially recovering electron-hole symmetry. The electronic structure of moire quasicrystals for Δφ = 30° differences reveal double moire features in the density of states with almost isolated van Hove singularities where we can expect strong correlations.