Band structure of twisted bilayer graphene on hexagonal boron nitride
Tommaso Cea, Pierre A. Pantaleón, F. Guinea
Abstract
The effect of a hexagonal boron nitride (hBN) layer closely aligned with twisted bilayer graphene (TBG) is studied. At sufficiently low angles between twisted bilayer graphene and hBN, ${\ensuremath{\theta}}_{hBN}\ensuremath{\lesssim}{2}^{\ensuremath{\circ}}$, the graphene electronic structure is strongly disturbed. The width of the low-energy peak in the density of states changes from $W\ensuremath{\sim}5--10$ meV for a decoupled system to $\ensuremath{\sim}20--30$ meV. Spikes in the density of states due to van Hove singularities are smoothed out. We find that for a realistic combination of the twist angle in the TBG and the twist angle between the hBN and the graphene layer the system can be described using a single moir\'e unit cell.