First-principles study on tuning electronic and optical properties in graphene rotation on h-BN

Graphene rotation on hexagonal boron nitride(h-BN) is of great significance in fundamental research and device exploration for its unique energy band structure, rich physical and chemical properties. Twisting angle technique of Graphene/h-BN heterojunction(G/h-BN) is considered as effective approach for modulating band and optoelectronic properties. In this work, G/h-BN heterojunction with different twist angles are discussed based on density functional theory and a critical angle of ∼13.17° is found which tends to rotate towards 21.79° or 7.34°. Band gap at the primary Dirac point is opened by 44 meV, and it changes from 0.7 meV to 7.1 meV when the rotation angle is twisted from 21.79° to 7.34°, which is related to the motion properties of carriers in different directions. Meanwhile, the optical properties of the twisting G/h-BN are very sensitive to the atom bonding. The calculated electron-photon interactions show that reflectivity and energy loss function have significant changes at different twist angles, indicates that the twisting angle can tuning the optical absorption spectrum and reflectivity.